A systematic literature review on risk disclosure research: State-of-the-art and future research agenda

This study presents a systematic review of the existing literature on corporate risk disclosure (RD). The study reviews 104 studies published in 51 high-ranked journals over the period 1999–2019 following the systematic literature review methodology developed and employed by past works. The results highlight the substantial knowledge gaps and inconclusive findings of extant literature in several aspects, including identifying avenues for further research in terms of research designs, settings, scope and theories. The findings also indicate that limited studies focus on developing countries, private institutions, and non-profit organizations. Similarly, our findings show that existing research that examines other firm and cross-country drivers of risk, such as national accounting, auditing, economic, governance, language, and legal systems, are not well documented. By contrast, our review illustrates that there is an increase in the number of studies published in recent years with over one-half of those that we review in this research published in the last six years of our sample period. Furthermore, our results suggest that past review studies have also focused excessively on the immediate firm-level characteristics, such as firm size, growth, leverage, value, and cost of capital. The findings of our review will be of great interest to academics, accounting standard-setters, managers and practitioners, policymakers, regulators, researchers, and students.


Introduction
Risk Disclosure (RD) disseminates information on the present and potential risks that organizations face that could affect their continuity, which is a crucial issue to stakeholders (Elamer et al. 2019. Therefore, RD could be one of the most important financial reporting categories to stakeholders. During the last two decades, several accounting standards and regulations were issued to modulate the RD process. In January 1997, the Securities and Exchange Commission (SEC) in the USA issued Financial Reporting Release (FRR No. 48) that required companies to publish information on market risks. In 2001, the German Accounting Standard Board (GASB) issued GAS 5 "Risk Reporting." In 2005, the International Accounting Standards Board (IASB) issued the International Financial Reporting Standard (IFRS 7) that came into effect in January 2007 to regulate the disclosure of financial instruments' risks. Besides the above major national RD reforms, the Basel Committee devoted Pillar 3 of the Basel 2 Accord that was issued in 2004 and subsequently revised in 2009 and 2015 to regulate RD in banks. Finally, many corporate governance codes have been issued by different countries around the world; most of these codes set out principles and have sections that focus on risk management and disclosure .
All this legislation underscores the importance of RD and, consequently, the increasing attention paid to RD over the past decades by academics, accounting standard-setters, policymakers, practitioners and regulators.
Despite acknowledging the importance of RD as indicated by the numerous RD regulations that have been issued by national and international regulators, existing literature has reported limited evidence on the value relevance of RD quality, its effectiveness, and the level of compliance with RD regulations, particularly in the financial sector Elshandidy et al. 2018b;Maffei et al. 2014). Also, despite the increasing number of empirical works on RD, review papers in this area are limited. Similarly, very few studies have been conducted in the financial sector; only 32 studies have examined samples of financial institutions and banks around the world.
These gaps in the RD literature in addition to our recognition of the importance of RD compared with other disclosure categories are among the main reasons to undertake this comprehensive systematic review of the existing RD research in both non-financial and financial institutions. The main objectives of this study, therefore, are to conduct a systematic review of the existing RD research; identify gaps and potential implications; and offer suggestions for future research. A crucial general benefit of a review study of this nature is to help readers, particularly academics, policymakers, practitioners, regulators, researchers and students to acquire a quick understanding of the state of research within an area from a few notable sources. Therefore, the main aim of our current review is to provide readers with an authoritative and comprehensive summary of the extant RD literature, as well as identify its limitations, and set the agenda for future research.
Consequently, we seek to contribute to the extant research by extending and complementing the existing limited review studies on RD by reviewing a larger number of studies that cover both financial and non-financial institutions in developed and developing countries over a longer period.
However, these studies appear to suffer from some weaknesses. For example, Ryan (1997) only reviewed RD research up to the mid-1990s and only those papers relating to equity risk within financial institutions. The review is currently well outdated, and seems less relevant to current researchers as new regulations and accounting standards have been developed significantly since the 1990s. Similarly, Ryan (2012) surveyed empirical studies on RD, but his study only focused on the relevance of firms' RD and how policymakers can encourage firms to improve RD quality. In addition, he only reviewed studies relating to financial instruments within financial institutions.
Meanwhile, Khlif and Hussainey (2016) conducted a meta-analysis review of 42 RD studies that empirically examined how corporate characteristics could affect RD. However, their review did not include studies that examine the governance determinants and value-relevance of RD, as well as studies conducted within financial institutions. Elshandidy et al.'s (2018a) review covered a limited number of RD studies, consisting of only 32 studies between 1999 and 2016. The authors classified these studies into just two main themes: (i) studies that examined the incentives of RD; and (ii) those that examined the RD informativeness. Finally, Tahat et al. (2019) reviewed just 19 studies conducted within financial institutions. However, they failed to identify and review theoretical studies (e.g., resource dependence theory and institutional theory).
To overcome the above limitations and unlike the previous RD review studies, we review the highest number of RD studies to date. The review covers 104 studies in both financial and nonfinancial sectors published over the 1999-2019 period in 51 top-ranked journals. Specifically, we classify the sampled studies into six different themes: (i) RD practices and characteristics; (ii) determinants of RD; (iii) consequences of RD; (iv) compliance with RD regulations; (v) new disclosure measurement methods; and (vi) disclosure on internal controls and risk management systems. Thus, despite our multi-disciplinary focus, we explore the development of a broad range of theoretical perspectives instead of only concentrating on a few, such as resource and agency theories, and highlight the emerging theories in this field of research. Furthermore, this review focuses on different aspects of RD research covered by past studies, including RD measurements, contexts, and constructs along with identifying and discussing avenues for future research in these areas.
The remainder of the study is organized as follows. Section 2 explains the methodology. Section 3 presents the systematic literature review that covers 104 studies. Section 4 discusses financial versus non-financial institutions RD research. Section 5 discusses the study's implications. Section 6 presents the literature gaps and offers new directions for future research, while Section 7 concludes.

Methodology
We follow two key studies that provide guidelines on how to prepare a creative systematic review study. Tranfield et al. (2003) provide a methodology to conduct a systematic review in management studies, and  similarly presents creative suggestions on how to conduct a review study. Tranfield et al.'s (2003) methodology is followed by some studies, such as and Beer and Micheli (2018) and Franco-Santos and Outlay (2018). Tranfield et al.'s (2003) methodology explains three stages that can be followed to conduct a review study, which we have applied in this study: (i) planning a review; (ii) conducting a review, and (iii) reporting & dissemination. The planning stage starts by elaborating on the need for this review. After a careful review of the disclosure literature, we found only five review studies with significant limitations, which reveals an urgent need for a comprehensive systematic review of the existing literature. Table 1 compares the five extant review studies to our study to highlight similarities and differences.
Insert Table 1 about here Another step of the planning stage is to develop a review protocol. Transfield et al. (2003, p. 215) stated: "The protocol is a plan that helps to protect objectivity by providing explicit descriptions of the steps to be taken." Accordingly, we construct a six-step protocol, as shown in Figure 1. The first step is to create a search list of the relevant RD keywords. The constructed list includes "Risk Disclosure, Risk Reporting,Risk Information,Risk Dissemination,IFRS 7,GAS 5,FRR No. 48,Pillar 3

of Basel 2 Accord, Disclosure on Weaknesses of Internal Control and Risk
Management Systems, and Financial Reporting of Risk". These keywords are the most commonly used in the RD literature. We also review the lists of references at the end of the reviewed sample to pick up any related study. Next, we searched for related articles on the websites of databases and search engines using keywords identified in the pre-determined search list. We depended on two leading search engines (https://www.google.com and https://scholar.google.com/ in addition to several common databases, such as Emerald, ScienceDirect, IEEE Explore, JSTOR, SpringerLink, Wiley Online Library, and ProQuest.

Insert Figure (1) about here
The third step is to determine the selection criteria to identify which studies to include, where five criteria have been set and applied. First, RD should be a central focus of the study.
Second, the study should be published in an Online Research Journal, where online-published papers, e-theses, or SSRN studies are excluded. Third, the study should be written by academic researchers (i.e. studies published by professional bodies are excluded). Fourth, the study should be written in English. Finally, to ensure the quality of the review studies, we only choose studies published in journals listed in the AJG2018 Journal Quality guide, whereby all journals should be given a rank from 1 as the lowest to 4* as the highest quality, both the 4 and 4* are given the same weight.
These criteria are set to ensure a comprehensive and quality review of RD studies. We focus only on studies published in academic journals. We also exclude working and unpublished studies because these papers are at an early stage and were subject to many revisions by the authors. This was in line with Habib (2012) who excluded working and unpublished papers, stating that these papers are not adequately reviewed. Moreover, we exclude the research papers published by professional bodies, since these studies were not subject to strict reviews like academic studies.
The second stage, conducting the review, includes a systematic and comprehensive search process, selection of studies, assessment of studies quality, and insights extraction. We were keen to find and download the full text of each selected study and save it in a folder. The final stage of the review process was Reporting and Dissemination, as shown in Figure (1).

The Systematic Literature Review Outcomes
The outcomes of the systematic review are presented in the next sub-sections based on eight aspects: (i) studies classification; (ii) trend of RD research; (iii) research impact; (iv) measurement unit; (v) theories applied; (vi) country of study; (vii) RD category; and (viii) studies' results. Table 2 exhibits the studies distributed into two groups and six different themes. The total number of studies that meet the review screening criteria is 104 studies published in 51 online academic and English Journals during the 1999-2019 period. These studies are classified into two main groups: (i) studies on non-financial institutions and (ii) studies on financial institutions. The majority of studies, 69%, examine RD using samples of non-financial institutions (72 out of a total of 104), while the remaining studies, 31%, examine RD using samples of financial institutions (32 out of a total of 104). Each group is classified into sub-groups based on the studies' research objectives and themes. The non-financial studies are classified into six different themes based on their objectives, while the financial studies are classified into four different themes. The nonfinancial studies examine: (i) RD practices and characteristics; (ii) RD determinants; (iii) RD economics consequences; (iv) compliance with RD regulations; (v) proposed new model/index/ measurement methods to score the RD level; and/or (vi) the disclosure on weaknesses of internal control and risk management systems. However, the financial studies reviewed covered the first four themes only.

Classifications of RD Studies
Insert Table 2 about here Figure 2 shows all studies in the first chart, the non-financial studies in the second chart, and the financial studies in the third chart. The first chart shows that up to 40% of all studies (42 out of 104) examine the RD determinants, followed by 29% (30 studies out of 104) that examine the RD economic consequences Moreover, 14% of studies examine RD practices and characteristics, while 7% of studies examine disclosure on weaknesses of internal control and risk management systems.
The second and third charts show that 43% of the non-financial studies (31 studies out of 72) examine determinants of RD, compared with 34% of the financial studies that examine the determinants of RD (11 studies out of 34). For the third theme, 25% of the non-financial studies (18 studies out of 72) explore the RD economic consequences compared with 38% of financial studies (12 studies out of 32) that examine RD economic consequences in the financial sector. For the fourth theme, 7% of the non-financial studies examine compliance with RD regulations (5 studies out of 72), compared with 6% in the financial sector (2 studies out of 32). Figure 2 also shows that the disclosure on weaknesses of internal control and risk management systems is explored in the non-financial institutions in seven studies representing 7% of the non-financial studies, while no study was found to examine the same theme in the financial institutions.

Insert Figure 2 about here
These results imply that researchers have examined the determinants and effects of RD disclosure extensively. Therefore, more attention should be paid to the less examined themes such as the compliance with RD regulations and disclosure on weaknesses of internal control and risk management systems, particularly in the financial sector. Moreover, only three studies propose a model or a new method of disclosure measurementnamely, Beretta and Bozzolan (2004), Abraham and Shrives (2014), and Ibrahim and Hussainey (2019). The common motivation of the RD determinants' studies, such as those of , Abraham and Cox (2007), Dobler (2008), Ntim et al. (2013), and , is to answer the question: What triggers the disclosure of corporate risk information? They explore the effects of effective corporate governance systems and corporate characteristics on the manager's decision to disclose high-quality risk information. The motivation of the RD consequences studies, such as , Tan et al. (2017), and Kim and Yasuda (2018), is to provide empirical evidence on the economic feasibility of disclosing higher quality risk information that could motivate managers to disclose more risk information. Figure 3 shows the historical development of RD research published during the period 1999-July 2019. The year with the highest publications is 2015 with 11 studies (e.g., Elshandidy and Nier, 2015;Moumen et al. 2015;Filzen, 2015;Elbannan and Elbannan, 2015),  1999,2000,2003,2007, and 2019 but that, overall, 32 studies are published on financial institutions during the remaining years.

Insert Figure 3 about here
The very early studies in RD are these of , , and . Both  and  used a questionnaire methodology to explore RD in the UK. Institutional investors are found to ask for more risk information on how firms manage risks; use corporate reports to find risk information; and prefer the voluntary format. Moreover,  examined disclosure on the market risks imposed by FRR No. 48 in the USA during 1993-1996. They found that RD is correlated to the oil and gas price sensitivity. Likewise,  explored the disclosure on market risks imposed by FRR No. 48 during 1996 in the USA. The results indicate that most sample firms disclose quantitative and qualitative information on market risks.
On the other side, the most recent studies are these of Kang and Gray (2019), Ibrahim et al. (2019), and Ibrahim and Hussainey (2019). Kang and Gray (2019) investigated 185 financial and non-financial firms listed on the London Stock Exchange (LSE) during 2013-2014. They found that multinational firms may not disclose additional voluntary risk information if are operating under higher level country-specific risks. Ibrahim et al. (2019) investigated a sample of Saudi Arabia non-financial firms and found that some corporate governance mechanisms such as CEO-chairperson separation and audit committee effectiveness positively affect RD level. The most recent study by Ibrahim and Hussainey, published in July 2019, discussed the different concepts of Risk and presented a RD concept that complies with the risk pre-modern view, where risk should only cover the negative outcomes.

RD Research Impact
The research influence of the reviewed studies is assessed using two approaches. Firstly, the quality of the journal where the paper is published is reviewed where the journal quality guide (AJG2018) published by the Chartered Association of Business Schools (CABS) is used. Secondly, the citations metric of every paper is used based on google scholar at a specific point of time. Table 3  Insert Table 3 about here  Table 3 exhibits studies published in four top-ranked journals; while 12 out of the 14 are done on USA samples. First, five of these studies are published in the Accounting Review. The early three studies are those of , Linsmeier et al. (2002), and Jorion (2002).  was the first RD study published in the Accounting Review with citations of 236 since its publication. The study examines the informativeness of SEC's market RD in the USA. Linsmeier et al. (2002) was the next study that explored the influence of market RD as mandated by FRR No.

Articles' Research Impact (Journal Quality)
48 in a sample of USA firms during -1998, while Jorion (2002 examined the Informativeness of the Value-at-Risk (VaR) format in a sample of eight banks in the USA during 1995-1999. The most recent study is that of Kothari et al. (2009)  Accounting. The early studies published in that journal are Beretta and Bozzolan (2004) and Ahmed et al. (2004), while the study of Elshandidy and Shrives (2016) is the most recent. Beretta and Bozzolan (2004) suggested a RD framework and an index to improve the measurement of RD while Elshandidy and Shrives (2016) investigated determinants of RD (environmental incentives) and the influence of RD on market liquidity and investor-perceived risk in a sample of non-financial German institutions during 2005-2009. Moreover, eight studies were published in the British Accounting Review,  and  were the first studies published in the British Accounting Review on RD. The two studies used a questionnaire as a research method and approached institutional investors in the UK to discover their attitudes towards RD in their requirements for more disclosure on RD.
Afterwards, the study of  was published in the same journal, where many studies have followed  to define and measure RD level in annual reports.
In April 2019, Kang and Gray (2019) investigated the country-specific risks in the voluntary disclosure of a sample of British Multinational firms.

Articles' Research Impact (Citations)
Google Scholar publishes statistics on the citations of articles, yet it cannot be used solely to evaluate the research impact of the review studies. Different studies are published in different years, and older studies accumulate more citations. To consider the time-effect, we apply the formula CPY = Citations / (2019-publication year). The calculated CPY seems fair, as the later publications are compensated for as they would have a higher CPY compared with older studies with the same citations. This formula is used in the software "Harzing's Publish or Perish", available from https://harzing.com/resources/publish-or-perish. Dumay et al. (2016) used the same formula to calculate CPY.  Table 4 shows that the six most cited non-financial studies are: Doyle et al. The most cited study, Doyle et al. (2007), investigated the disclosure on weaknesses of internal controls in a sample of USA firms during [2002][2003][2004][2005]. The second most cited study, Kothari et al. (2009), investigated how disclosure could affect the cost of capital and analysts forecasts in the USA. The third most cited study, Ge and McVay (2005), investigated the disclosures on weaknesses of internal controls as imposed by SOX 2002 in the USA. The fourth most cited study, Campbell et al. (2014), explored the mandatory RD as imposed by SEC 2005 using a sample of USA firms. The fifth most cited study, , presented a definition of RD and explored some determinants of RD using a sample of UK firms. Finally, Ogneva et al. (2007) explored a USA sample and concluded that disclosure of internal control weaknesses is not associated with the cost of equity. Table 4 shows that the most recent non-financial studies are not cited, such as Ibrahim and Hussainey (2019) Panel B of Table 4 shows the CPYs of the financial studies. The studies of Nier and Baumann (2006), Perignon and Smith (2010), and Jorion (2002) are the top-cited financial studies with CPYs of 52, 38, and 20, respectively, representing 41% of the total CPY of financial studies.
The most cited financial study, Nier and Baumann (2006), explored 729 banks during 1993-2000 in 32 countries to find out whether the market discipline is an effective RD mechanism. The second most cited financial study, Perignon and Smith (2010) Figure 5 shows the studies' allocation based on different units used to measure the RD score, such as word, page, or index. Twenty-three studies use a manual index and checklist of items to manually score the RD level, from which 12 non-financial studies use an index. For example, Lopes and Rodrigues (2007) used a self-constructed index consisting of 54 items, including disclosures on derivatives' risks, interest rate risks, and credit risk. However, Marshall and Weetman (2007) used a coding checklist based on responses to a list of items of a questionnaire. Tauringana and Chithambo (2016) used an index to examine the compliance with IFRS 7 requirements, while Deumes and Knechel (2008)

Insert Figure 5 about here
The disclosure level can be measured using the number of keywords, sentences, pages, or a mix of these measurement units. Figure 5 exhibits that 12 studies use the word as a measurement unit. Moreover, nine studies examined the RD level in the non-financial institutions using the word as a measurement unit (e.g., Ge and McVay, 2005;Miihkinen, 2012;Campbell et al. 2014;Dominguez and Gamez;Abdallah et al. 2015;Martikainen et al. 2015;Filzen, 2015) while Three studies examined the RD level in the financial institutions using the word as a measurement unit Woods and Marginson, 2004;and Adelopo, 2017).
The risk-related sentence is found as the common measurement unit, where 36 studies (35%) out of 104 use it to measure the RD level, 29 studies use risk-related sentences to measure RD levels in the non-financial institutions, such as Abraham and Cox (2007), Linsley and Lawrence (2007), , and Ntim et al. (2013), and seven studies use this measure of RD levels in financial institutions (e.g., Oliveria et al. 2011b;Maffei et al. 2014;Al-Hadi et al. 2016;Al-Hadi et al. 2015;Elshandidy et al. 2018b).
However, only two studies measure the RD level in financial institutions using a page as a measurement unit.    (2015) used a dummy variable that equals one for the risk disclosers, other studies such as  used a checklist and did not use a measurement unit, while  conducted a survey study, and Chipalkatti and Datar (2006) conducted an event study. The popularity of agency theory in the RD research may reflect the fact that the relationship between financial reporting, information asymmetry, and agency costs is much more evident, and stronger, than it is with any other theory. We found that the signalling theory is the second most frequent theory in the review studies as well, with a frequency of 19 times, where 15 studies on non-financial institutions such as Rajab and Handley-Schachler (2009), , Elshandidy et al. (2013), Khlif and Hussainey (2016), Elshandidy and Neri (2015), and Allini et al. (2016) have used the theory. Moreover, four studies on financial institutions have employed the theorynamely, Helbok and Wagner (2006), , Al-Maghzom et al. (2016), and Elshandidy et al. (2018b). Elshandidy et al. (2018b) used the theory besides agency theory to explain the determinants of RD quality and its impact on market liquidity. This theory is relevant to RD as well, where one of its arguments is that managers could send signals about risks they face to change, confirm or correct perceptions of the interested parties about risks (Spence, 1973;. The theory also explains that managers may use disclosure to send signals to distinguish their performance from others.

Frequency Distribution of Theories
The next most frequent theory is legitimacy theory, where nine studies are found to mention it. The theory argues that the management could be incentivised to release additional disclosure so that their firms would look more legitimate and socially responsible. Barakat and Hussainey (2013) used that theory to explain the determinants of RD quality in the banking sector, while Oliveria et al. (2011b)  On the other hand, the disclosed information could be misused, causing proprietary costs, as argued by proprietary costs theory (Abraham and Cox, 2014), since risk information could be sensitive, so its expected proprietary costs are high compared with the costs of other types of disclosure. Marshall and Weetman (2007) and Abraham and Shrives (2014) see that the management could be reluctant to release detailed risk information to not be misused by competitors. Moreover, eight studies employ that theory. For example, Hill and Short (2009) used the theory to explain the determinants of RD of IPO non-financial institutions in the UK during 1991-2003. Moumen et al. (2015) found that the proprietary costs could moderate the perceived RD relevance in nine MENA emerging markets. Abraham and Shrives (2014) concluded that proprietary costs could motivate managers in the UK to disclose symbolic rather than substantive information.
Finally, Figure 6 shows that 10 theories have been used in the review studies just once, such as the Fuzzy Set Theory (Dia and Zeghal, 2008), the Upper Echelons Theory (Al-Maghzom et al. , the Efficient-Market Theory , and the Management Entrenchment theory as mentioned by Barakat and Hussainey (2013).

2016), the Neo-institutional
Moreover, arguably Hope et al. (2016) is the only disclosure study that imported a theory from psychology (construal-level theory) to explain the economic benefits of specific risk-factors disclosures in a sample of USA firms during 2006-2011. This invites future researchers to develop RD research by employing any of these rarely used theories. Furthermore, although the capital need could be a motivation to encourage managers to improve the disclosure quality, the capital need theory is not mentioned in any of the review studies. Table 5 shows the distribution of RD research in both developed and developing countries.

Insert Table 5 about here
Second, Panel A of Table 5 exhibits only three developed countries dominate the RD research in all countries with a percentage of 35% (59 times out of 168); the USA (28 times with a percentage of 17%), the UK (22 with a percentage of 13%), and Italy (9 times with a percentage of 5.3%). This implies that more than a third (35%) of the RD research is concentrated on only three developed countries, and the remaining two-thirds are distributed over 46 developed and developing countries. The three countries account for 45% of the RD research in the developed countries.
Further, Panel (A) shows also that RD research on non-financial institutions is concentrated on only 12 developed countries, while RD research on financial institutions is distributed among 33 countries.
Examples of studies that examine RD using USA samples are  Examples of studies that examine RD in Italy include Beretta and Bozzolan (2004), , Elshandidy and Neri (2015), and Allini et al. (2016).
Third, Panel B of Table 5 exhibits the RD research in the developing world which represents less than a quarter (21%) of the total RD research around the world (36 times out of 168) distributed in 15 developing countries. Panel B shows also that three developing countries account for more than a third (36%) of RD research in the developing world, Saudi Arabia with a percentage of 14% Arabia. In Malaysia as a developing country, three studies examine RD in the non-financial sector (e.g., Amran et al. 2009;Othman and Ameer, 2009;Abdullah et al. 2015). In Kuwait, no study is found to examine RD in the non-financial sector, while RD in the financial sector was examined in three cross-country studies 2017a). It can also be noticed in Panel B that RD research in the Arab region dominates, where seven countries out of the total 15 developing nations are Arab Countries; Saudi Arabia, Kuwait, the UAE, Egypt, Oman, Bahrain, and Qatar. The RD research in these seven countries represents 74% (24 times out of 35) of the RD research in all developing countries and 14% of the RD research in all mentioned countries.
Finally, 23 studies use international samples of more than one country to examine RD.
Eight of these studies used samples of non-financial institutions Dobler et al. 2011;Khlif and Hussainey, 2016;Elshandidy and Neri, 2015;Abdallah et al. 2015;Moumen et al. 2015;Moumen et al. 2016). The remaining 15 studies use samples of financial institutions of several countries (e.g., Nier and Baumann, 2006;Barakat and Hussainey, 2013;Al-Hadi et al. 2016;Malafronte et al. 2018;Neifar and Jarboui, 2018). Moreover, Table 5 shows the non-financial institutions are examined in individual studies 60 times and in cross-country studies 11 times, while the number of times that the financial sector is examined in individual studies is 16 compared with 81 times in cross-country studies. Table 6 shows the distribution of RD studies based on the RD category. Overall, Table 5 exhibits that 46% (48 out of 104) of all studies examine both voluntary and mandatory RD combined, followed by mandatory RD (35%), and followed by voluntary RD (19%). The review studies are classified into eight groups based on eight RD categories, as shown in Table 6.

Frequency Distribution of Studies by RD Category
Insert Table 6

about here
First, 65% of the review studies (68 out of 104) examine RD in general and do not mention a specific type of RD, such as Carlon et al. (2003), Linsley and Lawrence (2007), Elzahar and Hussainey (2012) (2002), Liu et al. (2004), Chipalkatti and Datar (2006), and Perignon and Smith (2010). Furthermore, two studies explore the disclosure on the foreign exchange risk.   Furthermore, four studies investigate an individual type of market risks, such as the disclosure of interest rate risks , the disclosure of credit risk , the disclosure of risks associated with liquidity (Asongu, 2013), and the disclosure of risks associated with derivatives . Furthermore, Woods and Marginson (2004) is the only study that examines the RD of financial instruments as imposed by FRS 13 in nine banks in the UK in 1999. Meanwhile one study by Othman and Ameer (2009) examined the RD of financial instruments and level of compliance with FRS 132 disclosure requirements in Malaysia. Finally, Lopes and Rodrigues (2007) investigated the determinants of mandatory RD on financial instruments as required by IAS 32 and IAS 39 in Portugal in 2001. It is noteworthy that IFRS 7 is the most recent accounting standard on disclosure of financial instruments that have been effective since January 2007. Further, the FRC in the UK withdrew FRS 13 and replaced it with FRS 29, which is derived from IFRS 7.
Fourth, seven studies investigate the disclosure of weaknesses of internal controls and risk management systems. Five of these studies investigate this RD type in the USA as mandated by sections 302 and 404 of the SOX Act Ogneva et al. 2007;Doyle et al. 2007;El-Gazzar et al. 2011;. One study, Deumes and Knechel (2008), investigated the voluntary disclosure on the internal controls and risk management systems in the Netherlands, while Hill and Short (2009)  This study is one of the rare studies that used Python programming language to gather risk factors from the 10-Q Filings. Sixth, two studies by Oliveria et al. (2011b) and Neifar and Jarboui (2018) examined the voluntary operational risk on two banks samples one study by Fukukawa and Kim (2017) examined business risk using a sample of non-financial institutions. Finally, one study by Oliveria et al. (2011c) examined RD as imposed by a set of regulations such as IAS 1, IAS 30, IAS 32, IFRS 7 and Pillar 3 of the Basel 2 Accord. Lui et al. (2007), examined the disclosure of financial analysts' risk ratings based on a sample of USA non-financial institutions and concluded that analysts play an important role as providers of risk information.

Thematic Results
In this section, we present a thematic analysis of 104 studies, which are further classified into six sub-themes for discussion as illustrated in Figure 2 and Table 2. We conclude our discussions by identifying inherent limitations as well as potential avenues for future research under each sub-theme.

RD Practices and Characteristics in the non-financial institutions
Subsumed under this theme are 15 divergent studies, examining the RD practices and characteristics in non-financial and financial firms, respectively. Table 2 illustrates the summary.
Focusing on the non-financial firms, the analysis suggests that these studies report significant variations in the RD level.  considered institutional investors' expectations and reported that the RD level on foreign exchange risk management in the UK is lower than the institutional investor's needs. Conversely, Australian listed firms maintain higher levels (i.e. 72%) of risk information in their annual reports as noted by Carlon et al. (2003). Likewise, Lajili and Zegal (2005)  relatively higher compared to those reported by Lajili and Zegal (2005).
Turning to the RD characteristics, we observe higher levels of similarities in the selected studies. One of the most common characteristics across sampled studies is the nature of risk information, which is more qualitative (Lajili and Zegal, 2005;. Despite this, however, studies note inherent difficulties in extracting risk-related information from the annual reports and related corporate channels, Linsley and Lawrence (2007), for instance, observed that the readability of risk information is difficult and they recommend that directors increase the clarity of risk information. Considering the types of risks disclosed, Carlon et al. (2003) found that risk information disclosed in Australia is about risk management and identification of risks, whereas Dia and Zeghal (2008) found that risk information in Canada is about exchange rate risks, operational risks, and the risks associated with distribution activities and natural resources. Lajili et al. (2012) investigated executives' choices of disclosure and noted that managers tend to disclose more information on business risks relative to operational risks.

RD Practices and Characteristics in the financial institutions
Turning to the RD practices and characteristics in financial firms, the analysis based on seven distinct studies observes similar results about the RD level and quality across the sample.  analyzed the RD format of four US-based financial institutions for the year 1999 and reported that risk information presented in the tabular format improves the risk information comparability. Likewise, Linsley and Shrives (2005b) reviewed three surveys conducted by the Basel Committee and concluded that Pillar 3 of the Basel 2 Accord may not be effective in providing a complete picture of risks facing banks. They further argued that, owing to the fears of litigation or competitors, managers may feel reluctant to disclose all the risk information they possess. Focusing on 146 banks operating across 10 Asia Pacific countries, Yong et al. (2005) observed that the average RD level in the sampled banks is 35%, which is higher in developed countries relative to developing countries. Later studies confirm these upwards trends. For instance, Perignon and Smith (2010) observed an increase in the overall level of Value-at-Risk (VaR) disclosures in the USA. Similarly, Oliveria et al. (2011c) reported upwards trends in the RD level in Portuguese firms after the adoption of IFRS. As for the nature of RD, these studies largely agree that financial institutions do not provide a high-quality RD.  argued that this can largely be attributed to the banks' behavior in not explaining the underlying assumptions used in the development of risk estimates, thereby making it harder to evaluate the risk information disclosed by banks. Noting the exceptions within the field, driven by an analysis of 66 Italian banks for the year 2011, Maffei et al. (2014) submitted that the RD narratives were uniform, equal, and nonfinancial and that the RD of Italian banks complies with the Italy Central Bank regulations.
One of the primary limitations of this group of studies is that they merely remain focused on RD practices and its characteristics without accounting for the motives behind the managers' decisions to improve RD practices or quality. Notably, these studies do not consider the potential effects of firm characteristics in determining the extent, quality, content, and characteristics of the risk information disclosed. Most of the examined characteristics are related to time orientation and readability, and no study have been found to examine the RD characteristics with reference to the qualitative characteristics of useful accounting information as presented by the accounting conceptual framework. Besides, most of the studies are found to examine RD practices based on the level of disclosure rather than the quality. Future research may consider these aspects and fill this gap in the RD literature.

Determinants of RD Quality in the non-financial institutions
A key question addressed by the RD literature is: What drives some managers to disclose more risk information voluntarily while others disclose less or are reluctant to disclose any risk information at all? A set of studies try to answer this question by examining the influence of corporate governance on the managers' decision to disclose high-quality RD, while another set of studies try to answer the question by examining the influence of corporate characteristics. The results of the first group on the influence of corporate governance are a bit competing. For example, Abraham and Cox (2007) discovered that independent directors on boards have a substantial positive association with RD. Similarly, while audited by the Big-4 firms, Oliveria et al. (2011a) found that RD levels rise in organisations with a higher proportion of independent directors.  found that board diversity, board size, and independent directors all improve RD levels, while Elshandidy et al. (2013) discovered that companies with higher board independence and effective audit environments have higher aggregated RD levels, and Elshandidy and Neri (2015) found that independent directors on boards improve both voluntary and mandatory RD. However, a few studies found this relationship insignificant such as  and Dominguez and Gamez (2014). A related literature stream exploring the corporate characteristics as determinants of RD quantity and quality reports mixed results. Guided by the agency and resource dependency perspective, a clear majority of empirical studies argue for firm size as one of the main determinants or RD. These studies reason that larger corporates with abundant resources and a larger shareholder base are required to provide more information to mitigate the information asymmetry as well as to sustain investors' confidence (Watts and Zimmerman, 1983). These arguments are further extended by the stakeholders' theory, which hypothesizes that managers of large organizations are expected to satisfy diversified stakeholders relative to their counterpart representing smaller firms. Numerous empirical studies support these theoretical arguments, demonstrating a positive relationship between firm size and RD level and quality Elshandidy et al. 2013;Amran et al. 2009;Taylor et al. 2010;Allini et al. 2016;Marzouk, 2016). Constrained by the statistical significance, a few studies remain inclusive on the said association (e.g., Hassan 2009;Rajab and Handley-Schachler, 2009).
The company risk exposure is another determinant of RD. While earlier research, such as Linsley and Shrives (2005a) and Konishi and Ali (2007), found no effect of risk level on RD level, more recent research contradicts this. According to Elshandidy et al. (2013), companies with higher levels of various sorts of risks supply larger amounts of aggregated and voluntary RD. Similarly, cross-listing is another corporate characteristic that is explored by RD literature.
According to the signalling theory, cross-listed corporations are more inclined to provide positive signals about the risks they face and to reveal risk mitigation techniques to make their securities more appealing in international markets . The empirical data on this premise is contradictory. Cross-listing and RD level were found to have a substantial positive association by Lopes and Rodrigues (2007), Abraham and Cox (2007), and Rajab and Handley-Schachler (2009). However, no significant influence was found by Konishi and Ali (2007), Elzahar and Hussainey (2012), and Marzouk (2016). Finally, leverage as a corporate factor of RD is investigated. According to the agency theory, highly leveraged corporations may incur higher agency costs due to creditors, and that additional information may reduce these costs (Jensen and Meckling, 1976). As a result, leverage is expected to be a positive determinant of RD. The  Dominguez and Gamez (2014), and Allini et al. (2016) found no statistical significance to support or refute these findings.

Determinants of RD Quality in the financial institutions
Turning to the financial firms, three studies explore corporate governance mechanisms as determinants of RD and find a positive effect Al-Hadi et al. 2016;Al-Maghzom et al. 2016). Barakat and Hussainey (2013) found that outside board directors, active audit committees, concentrated outside non-governmental ownership, and the existence of powerful independent bank supervisors are positive determinants of RD quality. Likewise, Al-Hadi et al. (2016) found that risk committee size, qualifications, and independence are positive determinants of RD quality. Al-Maghzom et al. (2016) reported that outside ownership, the frequency of meetings of the audit committee, and board gender are positive determinants of RD level, while board size is found to be a negative determinant. On profitability, Helbok and Wagner (2006)  Board in Islamic banking and finance industry should be further investigated. These are some potential areas of research interests that we identify, and we encourage future researchers to consider these key aspects when studying RD.

Economic Consequences of RD in the non-financial institutions
The usefulness and economic benefits of RD are well debated in the RD literature streams (e.g., ICAEW, 1997;Kothari et al. 2009;Moumen et al. 2015).
However, the empirical evidence on the economic consequences of RD quality and the variables affecting its economic usefulness are scarce.  recognized that the disclosure literature provides poor empirical evidence on the economic consequences of RD quality and further argues that empirical evidence of the usefulness of RD potentially inspire directors, managers, and regulators to consider the RD quality when preparing annual reports and in setting the accounting regulations. This justifies the invitation of recent studies such as Kravet and Muslu (2013), , Campbell et al. (2014), Khlif and Hussainey (2016), , and Ibrahim et al. (2019), who call for the economic consequences of RD to be examined. Table 2 shows that a quarter of non-financial studies examine the economic consequences of  Hope et al. (2016) noted that more specific risk information helps analysts better assess the fundamental risk in a sample of USA firms whereas Heinle and Smith (2017) found that more risk information could reduce the cost of capital, particularly the disclosure of systematic risks, in a sample of USA firms. Tan et al. (2017) observed that synchronicity is inversely related to the RD level in China. Later studies such as Kim and Yasuda (2018) report that mandatory RD helps improve the investors' assessment of firm risk in Japan, while Li et al. (2018) concluded that higher RD improves the corporate investment efficiency in China and that the effect is more prominent when the RD tone is more positive.
Common recommendations derived from these studies call for more research on the economic usefulness of RD. For example, Kravet and Muslu (2013) and Campbell et al. (2014) recommended investigating the influence of RD quality on debt markets, debt pricing, and credit ratings' changes whereas  encouraged more research on the influence of RD quality on information asymmetry. Moreover,  recommended investigating the influence of disclosure on internal control weaknesses on the operating and business decisions effectiveness. Elshandidy et al. (2016) recommended using interviews and questionnaires to recognize the investors' real perceptions of the disclosed risk information, and Kim and Yasuda (2018) recommended future research to investigate the effect of RD quality on the cost of capital. Table 2 exhibits 12 studies that investigate the value-relevance of RD in financial institutions with a ratio of 37.5% of the reviewed studies focus on financial institutions (12 out of 32 studies), covering the period 2002-2018. Ten of these studies provide significant evidence on the value relevance of RD, while the remaining two remain inconclusive on the usefulness of RD. Jorion (2002) and Liu et al. (2004) found that Value-at-Risk (VaR) disclosure is informative in the prediction of trading revenues variability, return variability, and total risk in the USA while Ahmed et al. (2004) alleviated concerns about the usefulness of market RD requirements in the USA, while Nier and Baumann (2006) reported that banks that disclose more information on their risk profile limit their default probability. Elbannan and Elbannan (2015) found a significant positive association between RD and operating performance and market valuation of a sample of banks and concluded that banks with a higher RD earn higher profitability and market share. On the other hand, Al-Hadi et al. (2015) reported a significant negative association between mandatory RD and the implied cost of capital. However, both Woods and Marginson (2004) and Chipalkatti and Datar (2006) found no evidence for the usefulness of RD. Woods and Marginson (2004) further intimated that RD in the UK annual reports is too general, incomplete, and difficult to use. Furthermore, Chipalkatti and Datar (2006), who did not find statistical support for their theorem that RD explains abnormal returns, concluded that the market RD in the USA does not provide useful information to investors. Adelopo (2017), on the other hand, found that the temporal nature of RD affects firm performance differently; the study further found a negative effect of historic RD on the current and future firm performance and an opposite effect was found when examining forward-looking narrative RD. Drawing on a research sample of 47 European insurance companies, Malafronte et al. (2018) observed a positive influence of RD on volatility, and the RD level, which translates into higher firm value.

Economic Consequences of RD in the financial institutions
Providing evidence on the usefulness of RD is an essential step to encourage managers and regulators to pay more attention to improving RD quality. However, this evidence is still in its infancy, considering the nature of high riskiness of banking business. Although the above-cited 12 studies provide some insights into the RD practices in the financial services firms such as banks, more evidence is required on the value-relevance of RD. Apart from a scant focus on the financial firms, these investigations have ignored certain aspects: for instance, they do not consider the effect of RD on analysts' recommendations to investors; neither do they examine the market reactions to the release of such information. To clarify this further, an event study is needed to recognize the immediate effect of risk information once released. Equally, the relative implications of RD on debt pricing and credit rating is yet another potential area for research which, to date remains unexplored. Furthermore, it also remains unclear how users of risk information perceive and use risk information. Finally, future research could gauge the perceived benefits of RD for those who request such information and may adopt a qualitative research approach to gather such information via interviews or by administering a questionnaire. Table 2 shows that five studies examine the compliance level with the RD mandatory regulations using samples of non-financial firms. Three studies investigate the firms' compliance level with the market RD regulations: , Blankley (2002), and Othman and Ameer (2009). Both  and Blankley et al. (2002)  about 50% of the sample companies do not provide disclosure on material business risks as required by the Australian governance framework. Last, Tauringana and Chithambo (2016) reported that the compliance level with IFRS 7 RD requirements among Malawian firms is 40% on average and that the non-independent directors and firm size and leverage are positive determinants of compliance with RD imposed by IFRS7.

Compliance with RD Regulations in the financial institutions
Thus far, we find only two studies that investigate compliance with RD accounting standards and regulations drawing sample from international banks.  investigated the effect of IFRS first-time adoption and compliance with IFRS 7 whereas Asongu (2013) investigated the compliance with disclosure requirements of Pillar 3 of the Basel 2 Accord.  finds that banks comply with IFRS 7 and that the length and quality of risk reports increased significantly after first-time adoption of IFRS 7 in 28 EU countries. Contrarily, Asongu (2013) found no evidence of the compliance of 20 top world banks with disclosure requirements of Pillar 3 of the Basel 2 Accord even after the 2008 financial crisis. Besides, the study noted that bank executives appear to comply more with RD accounting standards such as IFRS 7 relative to the RD regulations set by the Basel Committee, hinting at the personal preferences of the bank managers.
One of the primary limitations of this group is the scarcity of studies examining compliance with RD regulations. Despite its scope and usefulness in understanding the extent to which firms comply with RD regulations, which are designed to enhance the quality of RD, only a handful of empirical enquiries have been conducted to date: five studies focusing on the non-financial firms while two studies have been conducted in the context of financial services firms.
As stated above, financial services firms are among the most regulated entities. The significance of regulations and accords is such that the IFRS 7 aims to organize the disclosure of risks associated with financial instruments in the financial sector whereas Pillar 3 of the Basel 2 Accord is developed to organize disclosure of risks in the banking industry. Despite the significance of financial services firms in acting as the lubricants within an economy, only scant attention has been paid to such organizations. Consequently, issues pertaining to RD regulations in public listed companies in general and financial services firms remain unexplored. Empirical evidence addressing fundamental questions such as to what extent banks and financial institutions comply with the requirements of RD set by these regulations remain unaddressed in the RD literature. This study attempts to draw attention of interested researchers to this substantial area of research.

Theme (5): A Proposed Model/Index of RD measurement
In this fifth sub-section, we discuss three distinguished studies that propose or develop a new measure of RD quality. First, Beretta and Bozzolan (2004) proposed and applied an index to measure the quality of RD. Their basic theorem is premised on the notion that additional attention shall be paid to the quantifiable mechanisms behind disclosed information: rather than merely focusing on how much information is disclosed, the analysis shall conceive what information is disclosed and through what channels (the how part). The proposed index measures the RD from different dimensions: quantity, density, depth, and outlook. These authors argued that this index can be used to rank companies based on RD quality and further recommended applying their proposed index to investigate to what extent the RD quality be affected by the external regulations. Second, Abraham and Shrives (2014) developed a model to improve the value-relevance of RD in corporate annual reports, based on three research questions that can be used to assess RD quality. The authors reasoned that their proposed model provides a new perspective to measure the RD quality away from the word or sentence count. Unlike the index proposed by Beretta and Bozzolan (2004), Abraham and Shrives's (2014) model is based on two accounting theories: proprietary costs theory and institutional theory. In a third and most recent study, Ibrahim and Hussainey (2019) proposed a new definition of RD, as a set of new keywords to be used in scoring RD levels in the narratives of annual reports.
As noted in the review section above, several studies have proposed and examined different methods and techniques to evaluate the quality of financial reporting. From our review, only three studies discuss models or indices to develop the measurement of RD. Notably, the study proposed by Ibrahim and Hussainey (2019) is a standalone study that examined the measurement of RD and proposed a new definition of RD to measure RD more accurately. Despite the noted attempts, though, literature on developing RD measurement is still in the development stage and further investigations to extend and expand this line of research is timely. A plausible way forward is to consider importing techniques from other disciplines such as linguistics or computer science to help improve and facilitate the process of RD quality measurement.

Theme (6): Disclosure of Internal Controls Weaknesses
The disclosure on the weaknesses of internal controls and risk management systems is mandated in the USA by Sections 302 and 404 of the SOX Act. Several studies have investigated such disclosure as a risk information category. Among those, five studies focus on the USA-based firms and two others have considered firms operating in the Netherlands  and the UK ). Using a sample of US-based firms, Ge and McVay (2005) reported that such disclosure describes internal control problems, and risk in complex accounts. The study further noted that firms that disclose the material weaknesses of internal controls are those audited by the Big-4, hinting at the significance of audit quality. However, according to Ogneva et al. (2007), disclosure of internal control weaknesses is unrelated to the cost of equity in US-based firms; Doyle et al. (2007) clarified that firms that disclose material internal control weaknesses are smaller, younger, financially weaker, more complex, and have higher growth rates and El-Gazzar et al. (2011) cautioned that disclosure on weaknesses of internal controls could downgrade the firms' debt and may affect the credit risk assessment. Echoing with the above literature,  concluded that disclosure of internal control weaknesses, particularly when auditors issue an adverse opinion on internal control, could affect the operating and investment decisions negatively.
Unlike the previous studies that investigate mandatory disclosure, Deumes and Knechel (2008) observed a positive link between leverage and voluntary disclosure of internal control problems in the Netherlands, but a negative relationship with ownership concentration. They also stated that the level of disclosure varies depending on the firm's underlying risk exposure. Finally, Hill and Short (2009) discovered that IPO firms publish more forward-looking information but less internal control and risk management information in a sample of UK firms.
While these studies are important, they focus exclusively on non-financial firms. To the best of our knowledge, no study explores these relationships in the context of financial services firms, including banking corporations. Arguably, RD is one of the most important financial reporting categories and disclosure on the material weaknesses of internal control could be the most important risk disclosure category. For this reason, it is important that these potential research avenues be further explored by conducting empirical investigations, particularly in the financial services firms.
Plausibly, having an effective management control system is likely to reduce the occurrence of any potential risks, and is likely to improve the quality of the financial reporting and communication with stakeholders. Besides, disclosure on the effectiveness of control systems could be beneficial to users to inform them on the companies' strategies, policies and controls set to manage and assess risks effectively. However, this group of studies does not provide empirical evidence on the quantity or quality of such disclosure. Given its crucial role, the disclosure of internal controls needs to be improved and extended.

Financial versus non-financial institutions RD research
Our review above highlighted some differences regarding RD research on both nonfinancial institutions and financial institutions. First, studies that focus on the textual characteristics (e.g., readability, tone, boilerplate) of RD in financial institutions are rare. Studies on RD practices and characteristics of financial institutions in developing countries are under researched. Thus, more research would be key to understand what the antecedents and consequences of these textual characteristics of RD are. Also, information related to derivatives or financial instruments' major risk types needs further exploration.
Second, literature on determinants of RD in financial institutions are rare, especially in developing countries. This strand of literature could expand by examining the influence of CEOs' demographic characteristics and organizational preferences such as tenure, experience, compensation, age, risk orientation, gender, education and other personal characteristics on RD practices. The role of monitoring bodies such as Shariah Supervisory Board in Islamic banking and finance industry (Elamer et al., 2019(Elamer et al., , 2020a(Elamer et al., , 2020b could be further examined. Islamic banks are exposed to more risk and make information asymmetry acute agency and legitimacy issues. Thus, future research can also delve into Shariah Supervisory Board structure and their impact on banks' and companies' overall strategic decisions toward RD. Also, future research could also look at corporate governance reforms taking place internationally and investigate how these reforms have impact on RD practices. Institutional theory may possibly be an appropriate theoretical structure for such investigations.
Third, the usefulness of RD in financial institutions is still underdeveloped , considering the nature of high riskiness of banking business. Also, the reviewed literature in financial institutions have ignored certain aspects such as the impact on analysts' recommendations nor market reactions. How firms' RD would affect banks loan decision is not answered yet.
Evidently, we need more analyses to determine what and how RD practices should be prioritized in the effort to alleviate the information asymmetry.
Fourth, there is limited evidence on financial institutions' compliance level with the market RD regulations. Financial institutions are subject to more strict regulations and compliance standards (Elamer et al., 2020a;2020b). It would be interesting to better comprehend the crossnational discrepancy in compliance level with the market RD regulations in cross-country study and whether these compliance levels are partly explained by countries' political regimes or/and country governance quality. At the organizational level, future work could also investigate more questions related to Top Management Team (TMT) compensation elements in financial institutions such as base salary, cash bonuses, incentive plan compensation and stock options may drive compliance level with the market RD regulations. Furthermore, analysing the consequences of board diversity (Bufarwa et al., 2020) and RD could improve our understanding of the role of diversity in the boardroom and its subcommittees (e.g., Khatib et al., 2021).
Lastly, our review suggests that no previous research has done to proposed index or model to measure RD in financial institutions. Likewise, a potential avenue for future research would be to assess how financial institutions disclosure on weaknesses of internal controls and risk management systems could affect the quality of financial reporting in general and risk information. In fact, it is interesting that we did not discover any article dedicated to internal controls and risk management systems. Several opportunities also exist in terms of testing the effects of the moderating effect of cultural and economic traditions on RD.
Altogether, we call for future research to construct a better understanding of the role of RD in financial institutions especially in emerging economies. We similarly see avenues for future research to shed light on international governance trends, IFRS and Basel accords and how changes affect the RD quantity and quality.

The Study Implications
The comprehensive review we conducted has several implications for a range of interested parties. First, several opportunities exist for academic researchers to contribute to the measurement of RD in different contexts. As we have seen, only a few studies have been conducted on RD research in the banking sector, in developing countries, and on the value-relevance of RD.
Likewise, the disclosures of weaknesses in internal control and risk management systems are rarely examined, despite their importance as RD types. Additional research could be undertaken to introduce a valid disclosure measurement for these types of RD and to examine their economic consequences. There is a possibility that the involvement of experts in linguistics in determining further RD keywords may improve the ability of computer-based content analysis for identifying RD. However, further research is needed to understand the potential contribution of linguistics experts.
Second, three implications of accounting standard setters and regulators are identified in our study. First, it emphasises that IFRS 7 is limited to the disclosure of risks related to financial instruments. However, companies face different risks, and the market participants need information on all risks not only those associated with financial instruments. Our study implies that regulators and standard setters need to take serious steps towards issuing a new accounting standard that covers most of the business risks, like GAS 5 in Germany. Future researchers may be able to contribute by examining whether a comprehensive international RD accounting standard, like German GAS 5, is needed. To do this, you should prepare interview questions and questionnaires and speak to analysts, investors, and risk managers. Second, our review implies that there is a need for a regulation that organizes the disclosures on weaknesses in internal control and risk management systems, like the SOX regulations in the USA. Third, for the Basel Committee, the risk information is so important to banks' stakeholders, because of the risky nature of banks' activity. Therefore, it is highly recommended to obligate banks to follow the RD regulations issued by the Committee, such as Pillar 3 of the Basel 2 Accord and BCBS 239. This will satisfy the stakeholders' information need, reduce the information asymmetry between managers and stakeholder and this could lead to desirable economic consequences. Research on would help to inform regulators and standard setters about the benefits of RD to stakeholders and disclosing firms. This provides regulators and standard setters the information needed for a more informed costbenefit analysis of RD.
Third, our review offers interesting implications for corporate managers. The review results imply that there is a theoretical and empirical consensus on the value-relevance of RD quality (e.g., stakeholders appear to be better informed by RD). Managers should recognize the different benefits that their companies could gain from disclosing high-quality risk information. They should give high priority to disclose all types of risks, that they face, in their annual report narratives. They need to avoid using complex language and boilerplate risk statements in their annual reports. They need to use RD to inform stakeholders about risks their companies face and how they manage it. They should not use RD to obfuscating stakeholders by using impression management techniques.
Fourth, governance regulators could participate in improving the RD quality by expanding the corporate governance regulations to include obligatory rules for the disclosure of risks. The UK Corporate Governance Code (2014. p. 17) obligates directors to describe in the annual reports the principal risks facing the company and obligates the board to monitor the internal control systems and report on this review in the annual report. Governance codes around the world, particularly, those in developing countries should develop and issue similar disclosure requirements like those of the UK Corporate Governance Code. These codes need also highlight the roles of audit committee and risk committee directors in overseeing RD in the narrative sections of the annual reports. This will lead to a high-quality risk information that could be relevant for stakeholders' decision-making process. Overall, all interested parties must participate in improving the RD quality, managers should recognize the value-relevance of RD and provide high-quality RD, accounting standards' setters should improve the existing RD accounting standards or issue a new specialized one, and governance regulators should improve the governance codes and issue obligatory regulations of RD to improve RD quality.

Literature Gaps and Research Agenda
Our review summarizes and synthesizes the RD literature. In this section, we identify several gaps in RD literature and recommend ideas for future research. First, the review identifies IFRS 7 as the only accounting standards that requires companies to disclose risk information related to financial instruments. To date, the only comprehensive RD accounting standard is GAS 5, which has been issued and applied in Germany. However, we find the accounting researchers tend not to investigate the issuance of a similar international and comprehensive accounting standard, or even extend IFRS 7 to cover all risks. Further research could be carried out by proposing a framework for RD standard. In this case, qualitative research methods (e.g., interviews and qualitative surveys) could be undertaken to explore the perceptions of standard setters, other regulators, corporate managers as well as stock market participants about the proposed RD standard that covers all types of risk that companies face. It would also be interesting to factors that may affect the demand and supply of RD in annual report narratives. A cross-country study on the perceptions of a risk disclosure standard is also an interesting area for future research. To move this research agenda forward, we suggest that further research could explore RD (voluntary or mandatory) regulations have been effective in improving RD quality. Second, our review shows that only 31% of the reviewed studies (32 studies out of 104) use samples of banks and financial institutions, despite the fact that financial institutions are riskier than non-financial institutions. Furthermore, banks around the world apply special regulations, particularly for the disclosure of risks, such as Pillar 3 of the Basel 2 Accord. However, and based on our extensive search, only one study, Asongu (2013),  (2013) and Moumen et al. (2015) are the only two studies that explored the influence of moderator variables on the economic consequences of RD quality. This suggests that further research could consider other moderating variables, such as the existence of risk committee, the readability of annual reports, market condition, and proprietary costs. Moreover, further empirical evidence is needed on the influence of RD on bonds' ratings, share valuation, debt pricing, credit rating, firm value, cash holdings, trade credit, investment efficiency, or cost of debt. El-Gazzar et al. (2011) may be the only study that explores how RD could affect debt rating changes. Moreover, Moumen et al. (2015) may be the only cross-country study that investigates the value-relevance of RD in non-financial companies, which suggests that further cross-country studies on the value-relevance of RD will be needed in the existing literature. Further research is needed to examine the usefulness of RD quality, particularly in the banking industry. Further research may examine how analysts and investors perceive, use, and benefit from the disclosed risk information. It would be interesting to explore whether the medium used to disclose risk information (e.g., annual reports, interim reports, corporate website, corporate social media, auditor report, conference calls and press release) affects its usefulness.
Fourth, 79% of RD research has been found to concentrate on developed countries. Three developed countriesthe USA, UK, and Italyaccount for approximately 35% of RD research around the world. However, RD could equally play a very effective market discipline role in the developing countries, as postulated by Elbannan and Elbannan (2015) and Pillar 3 of the Basel 2 Accord. This indicates, therefore, that further work is needed on RD in developing countries, particularly those with weak governance systems.
Fifth, although we found 24 theories that have been applied to explain managers' practices and motivations relating to RD, other relevant theories, such as capital needs theory, have not been used in the development of RD-related research hypotheses, despite the evident relationship between RD and the need to raise capital. This suggests that it will be appropriate for future researchers to consider new theories that have been rarely applied, such as capital needs theory, in future research so as to offer new insights and theoretical advancements.
Sixth, RD literature suffers from a major limitation. The literature on developing RD measurement is rare and future researchers are encouraged to investigate linguistics or computer science to help improve and facilitate the process of RD quality measurement. No study is found to examine the RD characteristics with reference to the qualitative characteristics of useful accounting information as presented by the accounting conceptual framework. Therefore, most of the studies are found to examine RD practices based on the level of disclosure rather than on the quality. It would be interesting to extend RD literature and provide a reliable and valid measure of RD quality.
Further research could also extend the governance-RD literature by examining the impact of CEO attributes such as horizon, tenure, experience, compensation, age, risk-orientation, gender, and other personal attributes on RD. At the time of writing no study has examined such attributes as determinants of RD quality.
Last, the literature on disclosure of internal controls effectiveness is rare despite its importance. This research avenue could be extended by researching how effective internal controls could affect the quality of financial reporting in general and risk information in particular. In addition, more empirical investigation is needed to explore different types of risk that are underresearched as far as we are aware. These includebut are not limited to -Brexit-related risk disclosure, COVID-19--related risk disclosure, and cyber risk. Further work could also examine RD practice following the UK's decision to leave the European Union or RD practice in times of the COVID-19 pandemic.

Summary, Limitations and Conclusion
This study comprehensively reviews RD research to date. Unlike past review studies, this review covers several conceivable aspects and sources of RD research, including theoretical and empirical studies relating to financial and non-financial institutions. The study examines eight The results of these reviews provide several research opportunities for future research. First, more research is needed to explore perceptions of an RD standard and the impact of regulations on RD. Second, more research is needed to examine the level, determinants and economic consequences of RD in financial institutions and to compare the findings with non-financial institutions. Third, future research could investigate the RD economic feasibility in variant financial communication channels (e.g., its impact on credit ratings, cash holdings and investment efficiency). Fourth, there is a need to explore RD in developing countries, specifically those countries with a weak governance system. Fifth, researchers need to consider other relevant disclosure theories (e.g., capital needs theory) in the development of risk-related research hypotheses. Sixth, future research needs to assess the quality of RD and how it is influenced by control risks as well as cyber-related risk, Brexit-related risk and COVID-19-related risks.
Our review has some limitations as follows. First, the review period is limited to the 1999-2019 period, so any articles published before or after this period have not been reviewed. Second, some RD articles were excluded from the review sample due to screening criteria. For example, RD articles published on SSRN or presented in conferences are not covered in the review. Third, only articles published in ABS-ranked journals are reviewed. All articles are given the same weight despite the wide variation in the journals' quality. We received a suggestion from a reviewer to exclude articles published within low-ranked journals, but we preferred to retain them in the interest of comprehensiveness. Fourth, a review of the measurement techniques of disclosure quality and quantity could have been a contribution; however, this was not presented by our study. Last, a review of the RD regulations could have been another contribution, but it was not covered.    Tables   Table 1: The Review Studies of RD Literature Ryan (1997) Ryan (