Extending mixed embeddedness to a multi-dimensional concept of transnational entrepreneurship

Migrant entrepreneurship in times of transnational migration go beyond locally serving markets and increasingly operate transnationally. The mixed embeddedness by Kloosterman and Rath has become the main concept to analyze such migrants’ entrepreneurship as it accounts for the multiple embeddedness of entrepreneurs in the variety of social and institutional contexts at multiple levels. This concept, however, does not yet accommodate the transnational dimensions of migrant entrepreneurship, which is still rather nascent in entrepreneurship research. Transnationalism is multi-dimensional in its nature as pointed out by migration researchers as Vertovec, and transnational migrants’ embeddedness appears to go beyond the notion of being simply dually embedded in two locations but rather should be conceived as being in one larger transnational field—though such aspects are not conceptually accounted in the mixed embeddedness approach. Taking this as a starting point, we propose to analyze the conditions that allow migrant entrepreneurs to engage in transnational activities. Our proposed framework bases on empirical research with 36 Polish entrepreneurs in the EU labor market, by drawing their opportunities from different levels and contexts of transnationalism. Following the research question on which levels and dimensions of embeddedness in the transnational field contribute to transnational entrepreneurship, we develop a novel refined framework of mixed embeddedness to analyze transnational entrepreneurship. It clarifies the entrepreneurial context by analytically and systematically subdividing components across dimensions (political, social and economic), and rearranging institutional elements and structures in each dimension according to respective levels (macro, meso, and micro). Emphasizing the role of conditions at the meso-level, the novel analytical framework better incorporates the multi-dimensionality and multi-levelling of transnational entrepreneurial activities of migrants. This model can be used as a tool for future comparative analyses of migrant entrepreneurship in different transnational contexts, it also contributes to the concretization of the transnational nature of transnational migrant entrepreneurship.


Introduction
Transnational migration has become the key phenomena of our times, leading to heated debates both in society and academia. Though migration research has long been debating transnationalism in different societal fields, it has only recently started discussing cross-border entrepreneurship. Entrepreneurship research, on the other hand, has produced substantial research on ethnic minority and migrant entrepreneurship, yet seems to have neglected the conceptual debates on the transnational nature of transnational migrant entrepreneurship until only recently. Transnational entrepreneurship is still a rather nascent field within entrepreneurship research. With the overlapping fields of interest, the interdisciplinary embedding of approaches from both entrepreneurship research and transnational migration literature is a fertile ground for research. Migration research complements entrepreneurship research in concretizing the transnational perspective in migrant entrepreneurship, especially regarding the migrant individuals' perspectives and practices of economic activities. Such integration of concepts from migration research into entrepreneurship can be observed not only on transnationalism but also its enhancement into issues of superdiversity (Sepulveda et al., 2011;Yamamura & Lassalle, 2019).
For analyzing ethnic minority and migrant entrepreneurship, mixed embeddedness has become the prevalent approach in migrant entrepreneurship, as it points at the multi-level embeddedness of migrants in their entrepreneurial activities (Kloosterman, 2010;Kloosterman & Rath, 2001), including their social embeddedness in migrant communities and in larger migration policies. The mixed embeddedness perspective allows comparative analysis of the complexly intertwined entrepreneurial contexts at different levels. However, although both entrepreneurship and migration researchers use the mixed embeddedness approach, the transnational element of transnational migrant entrepreneurship has not yet been sufficiently integrated into it and requires further conceptual debates. The transnational character of migration phenomena itself has been pointed out to be multi-dimensional and complexifying in its nature (Vertovec, 2007(Vertovec, , 2017). Yet, apart from analyses of different settings and case studies, there is still an analytical framework missing which captures the different contextual dimensions of transnational entrepreneurship and that can help understanding the role played by contextual conditions on the transnationalization (or not) of migrant entrepreneurs' activities. In addition, whereas the entrepreneurship literature has conceived transnational migrant entrepreneurship as dual embeddedness in different locations, the transnational migration literature (cf. debates on transnational spaces by Pries (2001) and Jackson (2004)) go beyond such an additive idea of embeddedness to emphasize the transnationality of contemporary migration (Glick Schiller et al, 1995, Vertovec, 2009). The elements of transnational fields in which migrant entrepreneurs are embedded, as for example the cross-bordering networks and institutional supports, cannot be separated between the countries of origin and destination, but overarch such borders and should be conceived parts of the overall transnational embeddedness.
Taking this as a starting point, this paper sets a new agenda for future research on transnational migrant entrepreneurship, looking the contextual conditions playing a role in the transnationalization the activities of migrant entrepreneurs. Following our research question of 'which level and dimensions of embeddedness in the transnational Page 3 of 23 Yamamura and Lassalle Comparative Migration Studies (2022) 10:14 field contribute Polish migrants' entrepreneurship?' this paper delivers a refined and multi-dimensional conceptual model to the mixed embeddedness approach. We base our analysis on an original qualitative fieldwork exploring the transnational activities of Polish transnational migrant entrepreneurs in the UK and EU contexts. The proposed analytical framework extends the mixed embeddedness concept, which already points at a multi-level approach to analysis (i.e., macro-, meso-and micro-level), to further different dimensions of society. We distinguish for each of these levels between social, economic and political (including policy) dimensions, bringing more clarity in the entrepreneurial contexts. This more comprehensive and refined approach of mixed embeddedness can concretize aspects of transnationality in entrepreneurship within migration research, and contributes to theoretical debates within entrepreneurship research. The proposed multi-dimensional analytical framework of mixed embeddedness could become a crucial step in more adequately and precisely analyzing different types of migrant entrepreneurship in society. This paper is structured as follows: it first provides an overview of recent developments in the literature concerned with transnational entrepreneurship, revising current approach of dual embeddedness to an understanding of transnational entrepreneurship as an overall transnational field rather than distinguishing between countries of origin and destination. The review also presents the benefits of applying the mixed embeddedness approach to study the social and institutional factors influencing entrepreneurial activities of migrants. The review clearly emphasizes the need for a multi-dimensional framework for the study of transnational entrepreneurship. Second, we introduce the context of our study, which focuses on transnational Polish migrant entrepreneurs in the UK and returnees to Poland. They are particularly interesting in a context of changing transnationality through the accession of Poland to the transnational single market in 2004 and then Brexit, after more than a decade of transnational mobility. We present how the qualitative fieldwork was conducted, exploring their activities as transnational migrant entrepreneurs. Third, we analyze our findings in an analytical framework, based on the proposed three dimensions with the three analytical levels of mixed embeddedness, with a focus on the crucial meso-level. In the fourth section, since transnationality occurs across all levels and dimensions, we provide an analytical differentiation of the scope and nature of transnationality in transnational entrepreneurship. We conclude by highlighting the potential implications of our multi-dimensional framework of mixed embeddedness for future comparative research on transnational migrant entrepreneurship.

Transnational migration and entrepreneurship
Transnationalism from the economic perspective originally had extended mostly on transnational corporations, discussing the overall contexts on macro-levels in which transnational labors are embedded, and then stretching also to labor market issues, especially regarding the transnational single market of the EU (Düvell, 2012;Verwiebe et al., 2017). With the increasing global migration, however, economic activities of individuals have also increased, leading to research on migrants engaging in self-employment and Page 4 of 23 Yamamura and Lassalle Comparative Migration Studies (2022) 10:14 entrepreneurial activities, led by both opportunity and necessity (Waldinger, 2005;Wilson & Portes, 1980). What followed is a growing number of research both on migrant and ethnic minority entrepreneurship, whereas the main focus of ethnic minority entrepreneurship tends to be on types of ethnic community contexts and the business strategies within the specific entrepreneurial environments in which migrant entrepreneurs are embedded (Yamamura & Lassalle, 2019;Zhou, 2004). Migrant entrepreneurship, on the other hand, focuses more on migration contexts and consequential specific entrepreneurial practices, distinguishing often cases according to migration types, such as diaspora, refugee, transnational or returnee entrepreneurship (Bagwell, 2018;Elo et al., 2019;Miera, 2008;Solano, 2019;Yamamura & Lassalle, 2021). Transnational entrepreneurship have been studied both in the US (Portes et al., 2002;Saxenian, 2003) and in the EU context (Lassalle & McElwee, 2016;Rusinovic, 2008;Urbano et al., 2011), with (unfortunately) less direct applications in the Global South contexts (Henn, 2012). By initially defining transnational entrepreneurship as cross-border activities occurring in two different locations, Drori et al. (2009) and Terjesen and Elam (2009) have extended the entrepreneurship literature on the transnational nature of the entrepreneurial activities themselves, which include sourcing, import to export. The aspect of 'dual embeddedness' , i.e., embeddedness in their country of origin and the country of destination remained the main focus of recent transnational entrepreneurship (Bagwell, 2018;Rusinovic, 2008). Relying on such transnational networks 1 and regular travels between the countries, they access specific resources, including financial capital, knowledge or products, to develop a competitive advantage (Brzozowski et al., 2017;Vershinina et al., 2019). The main perspective on being transnational in entrepreneurship refers to the going back and forth and the duality of embeddedness. Critique has been voiced on the neglect of the countries of origins when analyzing transnational migration entrepreneurship (Solano, 2019) and on the dominant ethno-focality of entrepreneurship (Yamamura & Lassalle, 2019).
We go further with the critique and point out that transnational embeddedness should be conceived as a transnational field or space which goes beyond secluded contexts of countries of origin and destinations (Crang et al., 2004;Pries, 2008). Dual or multiple embeddedness as discussed in entrepreneurship research reflect an additive understanding of migrants' lives and activities in two or more countries. Such an approach does not account the cross-border experiences, practices and networks as inherent parts of transnationalism beyond each of the locations as discussed in transnational migration research (Faist, 2000;Glick-Schiller et al., 1995;Vertovec, 2009). We therefore call for the transnational field as a useful framework as economic actors (e.g., transnational corporations, migration industries or transnational migrant entrepreneurs) and their activities are embedded in one field that encompasses several cross-bordering dimensions. The transnational element is indeed embedded at all levels of individual action or activism to the macro level of global culture. Yamamura and Lassalle Comparative Migration Studies (2022) 10:14 The mixed embeddedness perspective on transnational entrepreneurship Research on migrant entrepreneurship has placed particular emphasis on the social embeddedness of migrants within community networks of fellow migrants, for the maintenance of social ties and economic purposes (Haug, 2008;Portes & Sensenbrenner, 1993;Ryan, 2011). Migrant entrepreneurs have been observed to preliminary find resources within their own migrant community or within larger migrant groups (Aldrich & Waldinger, 1990;Kloosterman, 2010). The migrant community or the 'ethnic niche' (Waldinger, 2005;Zhou, 2004) is also the primary market for migrant entrepreneurs, at least for the initial stage of business creation (Lassalle & Scott, 2018). The mixed embeddedness approach has become the prevalent approach to analyzing such ethnic minority and migrant entrepreneurship (Bagwell, 2018;Jones et al., 2014;Kloosterman, 2010;Wahlbeck, 2018). It defines the contextual conditions of migrant entrepreneurship as a combination of social and institutional factors (Kloosterman & Rath, 2001). Indeed, the importance of institutional conditions and wider structures at different levels in the success of the economic activities of migrants has been pointed out (Engelen, 2006). They can include migration policies and statuses (as entrepreneurs or investors' specific visa), entrepreneurial support policies, and the access to financial institutions. The mixed embeddedness approach thus encompasses the social and the institutional contexts, in which migrant entrepreneurs find resources and explore markets (Kloosterman & Rath, 2001;Kloosterman et al., 1999;Ram et al., 2011), and it clearly distinguishes the macro-, meso-and the micro-level for entrepreneurial contexts.
The mixed embeddedness perspective indeed is an adequate basis to analyze transnational entrepreneurship (Solano, 2019;Yamamura & Lassalle, 2021), allowing a systematic analysis of the different contexts in which migrant entrepreneurs are embedded. It has the potential to clarify which activities and actions of transnational entrepreneurs and which factors of their surrounding entrepreneurial environment are crucial for the inception and the development of transnational entrepreneurship. However, the multitude of contexts in which transnational entrepreneurship is embedded has not yet been sufficiently integrated into the mixed embeddedness approach and requires further conceptual development. In fact, there are divergences of these levels in their dimensions depending on the disciplinary background of the analysis. Depending on the disciplinary approach, the crucial meso-level can refer to the community-level, e.g., when discussing social interactions and networks of migrant entrepreneurs; yet from a more policy-oriented view, the missing meso-level refers to the regional institutions and actors; whence the meso-level in economic terms yet again alludes to the ethnic niche market rather than individuals and their enterprises. What remains unknown is what makes a migrant entrepreneur engage with transnational entrepreneurial activities. Building on the literature (Vershinina et al., 2019;Wahlbeck, 2018), we define transnational entrepreneurship as: 'the activities of transnational migrants who actively engage in transnational cross-border trade, seeking for customers, suppliers and investors as well as accessing resources transnationally' . Situated at the cross-border intersection of different political, social and economic contexts, transnational entrepreneurs are embedded in transnational fields for both their migration and their entrepreneurial experiences (Nawojczyk & Nowicka, 2018;Nowicka, 2013;Portes et al., 2002). While almost all migrants-and therefore migrant entrepreneurs-are nowadays transnational migrants and maintain social embeddedness in different countries in the digital and globalizing age (Nedelcu, 2012), these transnational migrants are not necessarily engaged in transnational entrepreneurial activities, networks or markets. Therefore, transnational migrants can be either migrant entrepreneurs with transnational social and cultural ties or transnational migrant entrepreneurs with transnational entrepreneurial activities.
This brings us to our main proposal to develop the mixed embeddedness approach according to macro-, meso-and micro-levels. Building on migration and entrepreneurship research jointly, we further distinguish different dimensions of societal contexts, i.e., political, economic and social dimensions in the analysis of transnational migrant entrepreneurship. We take approaches on the levels from each of the disciplinary traditions, i.e., economics and business sciences for the economic dimension, sociology for the sociological dimension and to define the levels on the political dimension from administration sciences and policy-oriented economic geography.

Context of the study: Poland's accession to the transnational EU market
The study is placed in the context of changing institutional and political structures within the European Union. Polish entrepreneurs in the UK and other EU countries, and those who have since returned to Poland, make a particularly interesting case for the analysis of transnational entrepreneurship as they act as an exemplar of the contextualization of entrepreneurs in the transnational field. They have first become part of the transnational market of the EU through the accession in 2004, and later through the withdrawal of the UK from this same market (Brexit) roughly a decade later in 2016 with the referendum and effectively in 2020, have been withdrawn from the market again.
In May 2004, the UK opened its border to Polish migrants and other migrants from new accession countries (A8 and then Romania and Bulgaria). Based on the transnationalization of markets with the establishment of the Single European Market (SEM) and on the four freedoms, free movement of good, capital, services and people are guaranteed within the SEM. Thus, the macro-level conditions were made 'by default' transnational for all EU citizens. However, with the largest enlargement of the Community's history, most member states feared the large flows of migrant from the former Eastern bloc countries and placed restrictions on the free movement of workers from new member states for a transitional period of 7 years (European Commission 2020). Interestingly, the UK decided to maintain the access to EU migrant workers to their labor market. Whilst Polish migration was "nothing new to Britain" (Düvell, 2004), this policy lead to unprecedented inflow of A8 migrants, particularly from Poland (Drinkwater et al., 2009;Home Office, 2009; Institute for Public Policy Research, 2010). This post-2004 migration wave (Drinkwater et al., 2009) was composed of economic migrants and was facilitated by an ad hoc transnational migration industry of recruitment agencies for the different sectors of construction, agriculture or housing services (Garapich, 2008;Home Office, 2009;Lassalle & Scott, 2018). Over one million Polish workers and their families migrated and settled to the UK through such facilitated transnational migration conditions and regulations within the EU.
Transnationalization of Europe also changed the everyday practices of Polish migrants. Transnationalism has become part of their everyday lives, including with the rise of Page 7 of 23 Yamamura and Lassalle Comparative Migration Studies (2022) 10:14 online social media, grass-root activism and facilitated travel with low costs flights between Poland (and other A8 countries) and Western European destination counties, but also with evidence of return migration to Poland (Fihel & Grabowska, 2010). Among those Polish workers who had migrated to the UK, many have identified an opportunity to create businesses in different UK cities, using their transnational resources and networks to engage in entrepreneurship (Knight, 2015;Lassalle & McElwee, 2016;Vershinina et al., 2019). Whilst Brexit has since challenged perceptions of transnationalism among the population of A8 migrants in the UK (McGhee et al., 2017;Rzepnikowska, 2019), its effects are yet to be fully captured in a context of uncertain and evolving national political and economic conditions. What can be observed though is the emigration of Polish migrants from the UK, also as a reaction to xenophobic tensions towards the A8 migrants that coincided with the overall referendum to the Brexit. With them, some Polish entrepreneurs have returned to Poland to create new businesses or are transiting between Poland and other EU countries for entrepreneurial activities. Whilst they are transnational migrants, the transnational nature of their entrepreneurial activities (and the contextual experiences related to such activities) are yet to be explored. Although the contexts of Polish migrants in the UK and of Polish returnees in Poland are different, the actual transnational aspect of their entrepreneurial endeavors are comparable, i.e., their resourcing from the transnational networks and their actual transnational migration experience. Indeed, the focus of this paper is the proposal of a viable analytical framework for further comparatively analyzing political, economic and social dimensions in which transnational entrepreneurs operate, yet we acknowledge the differential inclusions of transnational entrepreneurs into the respective markets.

Methods: polish transnational entrepreneurship in the UK/EU
This research explores transnational entrepreneurship by analyzing the different contextual dimensions that influence the entrepreneurial activities of transnational migrants. We conducted a qualitative fieldwork with 36 Polish migrant entrepreneurs, located either in the UK (26) or who had returned to Poland (10) in 2018. These entrepreneurs were all embedded in transnational networks and communities in Poland, UK and in other countries. All entrepreneurs were Polish nationals and having migration experiences in different destination countries (USA, UK, continental Europe), they were embedded in transnational entrepreneurial fields. They all had started-up in the countries they were located in at the time of the interviews, and several had been entrepreneurs in different locations previously. These entrepreneurs operated in different sectors of the economy (see Table 1) and had different business relevant transnational connections. It can be challenging to identify migrant entrepreneurs and even more so returnees who have started-up (Vershinina & Rodionova, 2011). The 36 participants to this study were identified using snowballing within different entrepreneurial and community networks in the UK and in Poland. Interviews were conducted until we reached theoretical saturation.
We adopted an interpretive approach to our data collection, exploring the participants' experience of running a new venture. We conducted qualitative in-depth interviews with the entrepreneurs, and encouraged them to develop their own line of thoughts (Denzin & Lincoln, 2011). The interviews were conducted in the participants' preferred language Page 8 of 23 Yamamura and Lassalle Comparative Migration Studies (2022) 10:14 Table 1 Participants The "health" sector covers mainly businesses for import and exports of health products and not health services, whereas products can range from medicinal and pharmaceutical products to homeopathic ointments. For such products transnational entrepreneurs would collaborate with other SME laboratories and im-/export business partners (Polish or English) by the lead researcher, thence capturing nuances in their narratives. We started the interviews with a range of conversational topics covering: their migration experiences (including return migration when applicable), their entrepreneurial experiences (including their transnational activities, their access to resources and market) and their social practices both locally and transnationally. Interviews varied in length, ranging from 45 min to 2 h. Consistent with interpretivist research in migrant entrepreneurship, we then analyzed the data, looking for new themes and findings to emerge from the narratives (Klag & Langley, 2013). We first found that whilst all participants where transnational migrants engaged in transnational social fields, only some had transnational entrepreneurial activities of sourcing and access to market. 2 The transnationalization of entrepreneurship was particularly enabled or constrained by their embeddedness in different social, political and economic dimension at the meso-level. Using selected participants' narratives, we present these findings in section IV.

Theorization: building the analytical framework
Different academic disciplines, such as economics, sociology, geography, administration sciences or management, have their own definitions of the different macro, meso and micro levels as analytical units. Whilst representing these different levels into the model, we have constructed the levels according to three main societal aspects, i.e., the political, social and economic dimensions, capturing the dimensions in which transnational practices are embedded (Nowicka, 2013). For each dimension, we have adopted its respective disciplinary tradition in defining the macro-, meso-and micro-levels. 3 In political sciences, levels depends on the levels of decision-making in policy-making, starting from the macro, which is the national level "architecture of the state" (Roberts, 2020), political regimes and focusing on how the state evolves in relation to changing circumstances (Pollitt & Bouckaert, 2017). 4 The meso-level focuses on institutions and territories where reforms have been conducted and implemented. The role of support institutions and regional policy belong to the meso-level of analysis, as explored by the extensive regional science literature on entrepreneurship (MacKinnon et al., 2009;Saxenian, 2003;Urbano et al., 2019). Finally, the micro-level is the one of political activities of individuals (Landman & Carvalho, 2016), and their behaviors as citizens (Grimmelikhuijsen et al., 2017), including grass-root activism. 5 In the social field, sociology has long been concerned by the simultaneous articulation of micro, meso and macro analytical levels (Weber, 1922(Weber, /1971Crozier & Friedberg, 1977;Giddens, 1979;Bourdieu, 1980). Defining the micro as the level of agents and the macro as the level of social structures, sociologists have also highlighted the importance Yamamura and Lassalle Comparative Migration Studies (2022) 10:14 of the meso-level of groups, communities and organizational interactions in the analysis of social phenomena. In migration studies, this has encouraged theoretical developments on (transnational) networks and social embeddedness of migrants (Haug, 2008;Pries, 2008;Faist, 2010;Ryan, 2011).
In the economic field, the economic agent (the entrepreneur) is the focal point of micro-level analysis (as in micro-economics). Markets and communities represent the meso-level whilst the macro-level refers to the overall, national factors of productions. The macro-level also includes structural conditions set up by multi-and transnational corporations (M/TNCs) and the integration of firms in global value-chains that provide the framework for global economic activities (De Backer & Miroudot, 2014;Ponte & Sturgeon, 2014). Whereas micro-economic based approaches have been debated in migration research (as in the neo-classic migration theories), macro-economic perspectives have also led to theoretical development, such as the dual market theory (Piore, 1971).
The proposed analytical framework is indeed solely a model, thus, by principle a simplification of the actual much more complex and often interwoven societal phenomenon. Likewise, the dominance of disciplines is often overlapping in interdisciplinary social sciences. However, this model brings a clearer framework for future analyses and conceptualization of the rather disorderly discussions of (transnational) entrepreneurship.

Empirical findings
On the basis of the findings emerging from the analysis of the data, the following picture represent Polish transnational entrepreneurs' embeddedness into different fields and at different levels: Our findings show that what distinguishes transnational entrepreneurs from other migrant entrepreneurs (i.e., what makes their entrepreneurial venture transnational) are the conditions of their embeddedness at the meso-level. This emphasizes the importance of the meso-level of analysis in studying transnational migration practices (Faist, 2010) and transnational entrepreneurship (Portes et al., 2002). However, our analysis of the meso level in multi-dimensional and includes more than the transnational social networks revealing the role played by meso-level political and economic conditions. We find different patterns of activities between migrant entrepreneurs, and the meso level contribute to explain the difference of engagement of migrant entrepreneurs in transnational business operations, sourcing, and markets. We distinguish between transnational migrants who are entrepreneurs (and who are transnational individual migrant in their social and political practices) and transnational migrant entrepreneurs, who are engaging in transnational business operations, including through embeddedness in transnational supply-chain, industry-specific networks and markets.
The diverse political, social and economic contexts at the meso-level provide more (or less) favorable grounds for migrant entrepreneurs to engage with transnational activities. Whilst the macro-level transnational conditions in which transnational migrant entrepreneurs are embedded are of importance, these are not unique to them. Similarly, the transnationalism at the micro-level is a core characteristic for transnational migration, yet not decisive for the inception of entrepreneurship. Our findings show that the Page 11 of 23 Yamamura and Lassalle Comparative Migration Studies (2022) 10:14 consideration of the meso-level across these three dimensions is the key to understanding what makes transnational migrants into transnational entrepreneurs. We first present our findings on macro and micro-level contextual dimensions and the common role they play for all migrant entrepreneurs (summarized in Fig. 1 above). Focusing on our most original finding, we then present the crucial meso-level (Faist, 2010), providing a detailed account of the social, political and economic dimensions and how they favor or constrain the transnationalization of migrant entrepreneurs' activities.

Macro-level transnationalism
The findings first confirm the relevance of the macro-level framework in providing the conditions for transnational migration, and thus, transnational entrepreneurship. The migration of Polish individuals to the UK was made possible through transnationalization at the EU-level with the 2004 enlargement, when the UK waived the transitional provisions on the freedom of movement of most other EU countries. Interviewed Polish entrepreneurs confirmed this particular macro-level condition as the key to migrating to the UK after 1st May 2004 in search for employment and better livelihood. Poland at the time was facing high unemployment and the strong Stirling Pound was a further incentive for people to look for jobs in the UK. Initially, these migrants were sojourners and only working in the UK for a few months, before returning to Poland. However, with time, families joined, and migrants started to settle in the UK -such transnational circular and chain migrations were enabled by EU-accession. In addition, the transnationalization of the EU market provided numerous opportunities to grow their business, using transnational sourcing or by relying on transnational networks of corporations as clients, investors or main business partners if they wished. The macro-level of politico-institutional decisions made by national governments, but also international entities enabled transnational migration for Polish entrepreneurs and provides favorable conditions for their transnational entrepreneurial opportunities. Transnational supply chain networks were available to source manufactured products or services. Finally, among the younger transnational entrepreneurs of the study, we could observe the influence of a global culture on initiating entrepreneurship, thus macro-level social dimension of transnationalism, fostered by globalized media and different educational experiences abroad (in the UK, the USA, Denmark, and Germany). However, though macro-level conditions are crucial as a framework in which transnational entrepreneurs are embedded, these do not fully explain why the interviewed Polish migrant entrepreneurs started to engage with transnational entrepreneurial activities (including cross-border trade, the creation of transnational opportunities or engagement in transnational business networks). Indeed, the political, economic and social dimensions at the macro-level are identically faced by all EU migrants.

Micro-level transnationalism
There are different micro-level activities and responses at the level of the individual transnational migrant that characterizes all our participants. These depend on personal level of transnational grass-root activism (for example in cross-border religious and political action) in which some were engaged. Likewise, each participant had different intensity and frequency of engagement in individual transnational practices, as for example, watching Polish TV, maintaining contact with family and friends in Poland or across the world. Many of the post-2004 migrants have regular contact with family members or friends who had recently migrated to other EU or non-EU countries, using online social media (including Skype and WhatsApp). These micro-level activities of everyday practices of transnationalism do not however explain the conditions of their entrepreneurial activities. Transnational activities, such as sourcing, business collaboration with transnational partners or access to foreign customers, are in principle available to all potential migrant entrepreneurs. Yet, some did identify these opportunities whilst others kept focusing on local activities. What can explain the different entrepreneurial activities of these entrepreneurs regarding transnational entrepreneurship are meso-levels conditions across the three dimensions of the political, economic and social.

The crucial meso level of transnational entrepreneurship
First, the social dimension at the meso-level refers to social practices, characterized by access to specific social networks, further giving access to additional resources that entrepreneurs use for their business. We found that the social dimension of the mesolevel, whilst having the potential to facilitate the start-up of the business, often also constrains the engagement of migrant entrepreneurs in transnationalization activities. As Jan (who has no entrepreneurial transnational activities for his manufacturing business) says: I have a broad enough network of customers here in the UK. There are too many things I can do for mates who have their own businesses already Polish migrant entrepreneurs are embedded in their community of fellow migrants (see also : Ryan, 2011;Knight, 2015;Lassalle & McElwee, 2016). They socialize within the community, for a beer at a local pub, for sports sessions, for religious services, which are coupled to emotional and informational support from the community. Ad hoc media developed for the circulation of information for such social events (emigrant magazine, emito, glasgow24 fora and other social media groups), which were then also used when starting up. Rafał, who uses transnational sourcing for this car repair business, thus, being a transnational migrant entrepreneur in UK, accounts as followed: I love playing basketball. I have been practicing for many years. When I arrived in the UK, I did not know where to play. We created a forum on emito. 6 You know, to find information, where to find a good car repair service or where to by some tools for DIY. I started to see that there could be more good quality car repair shop. I started to test the waters, to ask people what they needed. I was advertising the business before I started.
Through such social practices within the community and because of shared culture, Polish migrant entrepreneurs better understand the needs of the community, which they see as opportunities for the development of their businesses. For example, Marta, as an entrepreneur in catering business, focuses on the migrant community, reflecting the more classical understanding of ethnic niche markets in case of transnational migrant entrepreneurship:

I am a Pole too. I know what the Polish people want. Which sausage, which juices, which ham to sell. Sometimes I do not know anything about a product. I don't eat much cheese so I ask my customers about their favorite ones.
In addition, some entrepreneurs break-out to the mainstream market. By being embedded in the host country society beyond their own migrant communities, they have discovered further opportunities for their business. The geographical point of reference in these cases can be the neighborhood rather than the ethnic towns or other areas where their co-ethnics concentrate. Tomasz, for example, who is a transnational migrant himself, but operates in the local community, recounts how he became more socially embedded with people living in the same neighborhood: I met so many people. I mean local people. They are British. We talk about football, Page 14 of 23 Yamamura and Lassalle Comparative Migration Studies (2022) 10:14 this is universal. We started to do this business, the IT service one.
Through the social embeddedness at the meso-level in the local neighborhood, they gained access to information, sourcing, labor and market. However, despite some evidence of social engagement with local people and serving the local market, some Polish migrant entrepreneurs remain mostly embedded in the Polish community, which also is their target niche market.
Regarding specific transnational business activities, the social dimension of the mesolevel is also where transnationalization can be achieved. We observe such transnationalization of business with several entrepreneurs who have established prior connections through studies or work experience abroad, as in the case of Janusz, a transnational IT business entrepreneur: I worked in the USA for 3 months. I did everything: waiter, cleaner, everything. Then I found a short-term job in IT as a coder. I work with them now. My clients are all over the world. As long as I deliver. I employ these Poles to work with me. We are a bunch of Poles, competing with Indians and Hungarians for US market.
Transnational entrepreneurial activities emerged when Polish migrant entrepreneurs purposefully seek for transnational connections which they could use for their business. This occurs not only in the IT sector, but also in other sectors, such as in the food sectors: We started to look for partners back in Poland. We did not know anyone. We have our family there but for the business, we knew no one. So, I actually went to Silesia and searched for partners from whom we could directly source our imports. This helped us to cut 30% on intermediary costs for a whole range of products. We only buy the bread here in the UK (Andrzej) Whereas some still aim for the Polish migrant community market and capitalize on access to further resources, others go beyond the migrant niche market by building on transnational social connections for their activities. Joanna, who builds transnational networks for her consultancy accounts: Along with favorable conditions at the macro-level, our findings show that the mesolevel is crucial in becoming transnational entrepreneurs. The social dimension is crucial in explaining the engagement of Polish migrants in transnational entrepreneurial activities, whereas difference can be seen on the business strategies regarding the market foci.
Second, the economic dimension at the meso-level relates to the specific sectoral and industrial conditions, as well as on the ethnic niche market opportunities Page 15 of 23 Yamamura and Lassalle Comparative Migration Studies (2022) 10:14 identified and created by migrant entrepreneurs. In the UK, the Polish-community niche market is large (with over 1 million Polish-born people in different cities in the UK) and brings sufficient demand for some migrant entrepreneurs, who remain economically embedded in the local community niche market: There is no need to look far away. There are so many Poles here in Glasgow. My salon is always full now" (Irena, who shows no transnational entrepreneurial activity) For these reasons, the migrant community niche market is often the sole market for Polish migrant entrepreneurs. However, the transnationalization of the EU market at the macro-level provides numerous opportunities to grow their business beyond the locally-based migrant community. Transnationally engaged entrepreneurs capitalize on these opportunities based on the meso-level conditions of the industry, engaging in transnational sourcing, networking and market access.

I work in IT right? I mean, I am doing infrastructure design for IT companies. I can work from anywhere, I am using platforms from the Silicon Valley, IT solutions from Hungary, and all similar things. I work in Poland now but my clients are all around the world. (Paweł)
Likewise, still in the IT sector:

My passion is Artificial Intelligence. This is my business. In AI, the applications are worldwide. I have some local clients, but all the others are in the USA. I am a supplier for larger firms in the Silicon Valley (Iwona)
The IT sector specifically enables and encourages transnationalization for entrepreneurs, but transnationalization of economic activities are not limited to this sector. Some entrepreneurial endeavors are based on other economic opportunities, often using the costs differential between different countries to identify appropriate industries and specific niche markets in which to operate.

The business model is simple here. I just buy in Poland and sell in the UK. This is so much cheaper to manufacture in Poland. I am like a broker. I bring business on both sides: to my Polish suppliers and to my clients here. (Michał, operating transnationally in manufacturing)
The economic dimension for transnational migrant entrepreneurship is often closely interlinked to the social dimension, with the transnational connections being crucial for the business. Yet, migrants differentiate between specific business and corporate connections from those opportunities arising from merely social interactions. Also, there are further economic impact at the meso-level such as barriers to labor market integration, potentially leading to entrepreneurship. As another transnationally operating entrepreneur in manufacturing accounts: But I could not really find a better job here. I remember, I went to an advisor at the job center to ask her: could I apply to this or that? But she could not understand my degree (a license, equivalent to a bachelor degree) and my work experience would not mean anything for a local employer. Really this was tough. (Bogdan) Despite formal macro-level policies supporting the EU-wide recognition of qualifications, they might not be recognized at their value on the labor market at the meso-level. These are barriers of economic dimension at the meso-level faced by migrants. Mesolevel economic conditions can lead migrants to entrepreneurship as a necessity, but also give new opportunities in the transnational field.
Third, on the political dimension, the meso-level refers to regional policies put in place and to business support agencies to which entrepreneurs have access. The specific meso-level political arrangements help explaining why some transmigrants entrepreneurs engage in transnational entrepreneurship. Scotland is an interesting case in this respect, being part of the complex political system of the UK, governmentally operating at the meso-level. It has a pro-migration agenda ('We are Scotland' campaign) and has launched specific government support policies for migrants and migrant entrepreneurs (Mwaura et al., 2018). However, the Scottish government has no autonomy on migration policies and liberalization (decided at the macro-level), which reduces the scope for tailored support. Such meso-level inequality in the political dimension is well illustrated in case of Polish entrepreneurs located in London, who benefit from further regional policy support and region-specific transnational economic connections to other major urban centers. Operating transnationally in the luxury industry, Magda remembers:

We moved to London from Sheffield [note: Northern England]. Being in London is like being in Vienna, Milan or Berlin for the business. All the diplomats are here for the Embassies, the Consulates. It could have been Edinburgh too [note: Scotland], but London is just more interconnected as a city than Edinburgh.
She went on explaining not only the potential she saw in the market, i.e., the availability of highly affluent customers for her luxury products in general, but also mentioned the presence of "powerful people" and their desires for "posh interiors" in their housings and buildings for representation purposes, helped her to establish in these networks in the context of London. She not only benefits from the presence of a transnational customer base, but more importantly the presence of business networks and of political institutions at the meso-level. Though indirect in the actual 'political' dimension, her case illustrates how the meso-level of politics can be reflected in transnational entrepreneurship this way, too.
Though formal institutional support at the meso-level can also be available, many Polish migrants are not aware of relevant regional support institutions, such as those that can provide small grants and advice to start-up and grow businesses (e.g., Business Gateway and Scottish Enterprise). Even when migrant entrepreneurs are aware of existing support institutions, they perceive them as useless to them. As commonly expressed during the interviews, entrepreneurs consider that meso-level institutional support are not designed for the needs of migrant but for those of local entrepreneurs. This mismatch derives from the fact that entrepreneurial support policies of the Scottish government are tailored to encourage the development of an entrepreneurial mindset, but migrant entrepreneurs desire technical support on bookkeeping, taxes and start-up capital: Indeed, most support to migrant entrepreneurs is for start-ups but neglects the potential of migrant businesses to access international markets and engage transnationally. Whilst such programs exist, entrepreneurs insist that the offer is not tailored to support their particular needs in receiving technical know-how and in activating transnational resources that they can leverage for their businesses. We observe a different perception of meso-level political support in the case of transnational entrepreneurs in Poland, where regional policy-makers are encouraging returnees to engage with transnational markets and activities, through favorable policies, financial and technological support. As Mirela, as a transnational entrepreneur who operates in the IT industry from Poland says: After I came back from the USA, I actually found some support here in the region. The [regional] government set up some support for entrepreneurs. We have a science park and some financial incentives. When I talk to them, they are all mentioning funding opportunities from Israel and markets all over the world.
Indeed, in the Scottish case, transnational entrepreneurship is not necessarily supported by the regional entrepreneurial ecosystem (cf. Mwaura et al., 2018;Spigel, 2017), yet other regions within Europe, especially in the context of return migration as well as border regions (see INTERREG projects) build on the economic potential of transnational entrepreneurship.

Discussion
As an answer to our research question on which level and contextual dimensions are crucial for the transnationalization of migrant entrepreneurs' activities, we found that the conditions of their embeddedness in the different economic, social and political dimensions considered at the meso-level are crucial. With a (perceived) mismatch between institutional support (political/policy dimension) and their needs, migrant entrepreneurs are drawn to look for resources in their migrant community networks and to focus on social embeddedness (social dimension). Those who have business-relevant connections identify niches and markets (economic dimension) and therefore have more potential to grow their businesses by engaging with their transnational social networks. Though there are interconnections between the meso-levels across the dimensions, differentiating these three dimensions is key to understanding the conditions under which migrant entrepreneurs can better start up and grow their business transnationally. The conceptual differentiation is also key for more precise policy recommendations to support the transnationalization of migrant entrepreneurship.

Multi-dimensional mixed embeddedness of transnational entrepreneurship
The accounts of migrant entrepreneurs demonstrate the presence of transnationality at all levels and across all three dimensions. The transnational context of the macro-level has significant influences on their activities, as free mobility and access to labor markets are enabled by EU policies. Factors such as the accreditation of qualifications or general access to support are the basis of any transnational migration. The micro-level of transnational practices is existent among all transnational migrants, too, whereas certainly the intensity differs individually. Yet, when it comes to the initiation of entrepreneurial activities, and particularly of transnational entrepreneurial activities, the degree and intensity of embeddedness at the meso-level becomes crucial.
The crucial level explaining transnational entrepreneurship has emerged to be the meso-level embeddedness of Polish migrant entrepreneurs. Here, all dimensions, i.e., economic, social and political, appeared important. Transnational entrepreneurs activate and benefit from social and economic resources in their transnational field for their entrepreneurial activities. The connectedness and embeddedness not only to their own migrant communities and migrant niche market, but also in the broader neighborhood local communities are crucial for the success of their businesses. In fact, having specific support and finding viable funding institutions have appeared to be important, whereas transnational migrant entrepreneurs benefit specifically from such transnational social and economic resources. This means that transnational migrant entrepreneurs are embedded in a transnational field where they can, e.g., source their products transnationally from supplies, through different transnational activities, networks and practices, which go beyond simply bridging dual embeddedness between different locations. Whereas transnational migrant entrepreneurs have access to transnational resources through their transnational connectedness, non-transnational migrant entrepreneurs are limited to local suppliers and markets. The difference in the transnational embeddedness and the mechanism of entrepreneurial activities between transnational and other entrepreneurs, thus, becomes more visible when focusing on the meso-level.
Moreover, what is interesting in the narrative of the Polish transnational migrant entrepreneurs is the lack of specific institutional support at the meso-level. Though regional development policies do offer support for the entrepreneurial ventures of migrants as well as of locals, the knowledge of such institution is scarce and migrant entrepreneurs rarely contact existing support agencies, which they identify as "not tailored to [their] needs". Polish entrepreneurs thus need to use their social embeddedness and economic resources at the meso-level, rather than benefiting from the institutional supports from the meso-level policy-side. This means that by targeting specific elements of the social and economic fields, such as connecting directly to migrant community networks as intermediaries (social field) and better advertising funding institutions and industry-specific networks in relevant channels (economic field), policy-makers could succeed more in supporting transnational migrant entrepreneurship.

Conceptual proposal: multi-dimensional mixed embeddedness of entrepreneurship
Empirical findings have demonstrated the usefulness of multi-dimensional approach in analyzing conditions of transnational migrant entrepreneurship. We propose an analytical framework that distinguishes not only the levels of analysis, i.e., macro-, meso-and micro-level, in the traditional understanding of mixed embeddedness (Kloosterman, 2010;Kloosterman et al., 1999). We also call for the analytical distinction of the dimensions of the (transnational) field in which entrepreneurs are embedded: the social, economic and political (Fig. 2) and cannot be reduced to the social context (Nowicka, 2020). Whilst the transnational element can be seen in all levels, such analytical differentiation between dimensions helps clarifying the influencing conditions for the engagement of entrepreneurs in their contextual embeddedness. Furthermore, taking the transnational field as the basis and not as an overarching level, the model better captures the transnational characteristics of each contextual dimensions, including, for instance micro-level political transnational practices. Transnational networks, practices and activities are, as demonstrated in migration research (Glick Schiller et al., 1995;Vertovec, 2009;Nowicka, 2013), inherently embedded in a transnational field, are not well reflected in the idea of dual embeddedness, in which the fields are separated from each other.
In fact, our model disentangles what is occurring across different dimensions in the transnational field. As we had started off with the critique on the missing transnational dimension of the mixed embeddedness as an approach to analyze the contexts of transnational entrepreneurship, transnationality and transnationalism has been studied from fairly different perspectives, reaching from migration (Faist, 2000;Vertovec, 2009) to transnational entrepreneurship scholarship (Drori et al., 2009). Whereas first debates within business and management studies on transnationalism were seen in the corporate contexts, distinguishing the terminologies between global, inter-, multi-and transnational operations, recent debates in entrepreneurship and international business also have the perspective of transnational practices of communities and individuals as economic actors (Portes et al., 2002;Bagwell, 2018;Vershinina et al., 2019;Yamamura & Lassalle, 2021). In the political dimension, the transnationality as a term has been initially used on grass-roots political activism that are connected across borders, but where it has also found resonance is the context of political economy, particularly on the transnational single market of the European Union, leading also to the mobility and practices of individuals as transnational communities or even a pan-European society. These different contexts in using 'transnational' demonstrate in fact how important it is to differentiate the dimensions of embeddedness of the transnational entrepreneurial field.
By proposing the multi-dimensional mixed embeddedness as a refined and more comprehensive analytical framework to the original mixed embeddedness approach, we clarify the embedded nature of entrepreneurial endeavors in contexts at different levels and across multiple fields or dimensions. This model accounts for the increasing complexity Page 20 of 23 Yamamura and Lassalle Comparative Migration Studies (2022) 10:14 in the interwoven embeddedness of (migrant) entrepreneurs in social, economic and political fields at different levels of analysis. Such analytical framework opens conceptual debates and enables comparative analyses of different contexts for transnational migrant entrepreneurship. As hinted through 'the crucial meso-level' (Faist, 2010); the social, economic and political embeddedness at the meso-level influence transnational entrepreneurship and this can be visually and analytically shown through our multi-level and multi-dimensional framework.

Conclusion
The mixed embeddedness approach, which emphasizes the importance to distinguish between macro-, meso-and micro-level contexts of migrant entrepreneurship (Kloosterman, 2010;Kloosterman & Rath, 2001;Kloosterman et al., 1999), has established itself as the main analytical framework for both ethnic minority and migrant entrepreneurship (Bagwell, 2018;Jones et al., 2014;Solano, 2019;Wahlbeck, 2018). Yet, as it becomes particularly clear in the case of transnational migrant entrepreneurship, a multi-levelled mixed embeddedness approach adds to the understanding on the embeddedness of migrant entrepreneurs but does not account for the different dimensions in which transnational migrant entrepreneurship is occurring. Also, the approach of entrepreneurship researchers to conceive transnational entrepreneurship as a mere dual (or multiple) embeddedness does not properly account for the transnational practices of migrants. We therefore apply the mixed embeddedness approach to the transnational field which goes beyond distinct countries of origin and destinations and reflects the transnational connections, networks and practices more holistically. Based on findings among migrant entrepreneurs and their engagement (or not) into transnational entrepreneurial activities, and to further improve clarity of the different aspects of embeddedness at each level of analysis, we integrate differentiated dimensions of the contexts beyond the vertical embeddedness of mixed embeddedness. Dimensions of entrepreneurial environments, i.e., social, economic and political fields, have been discussed in transnationalism research and mentioned also in migrant entrepreneurship, yet a systematic analytical framework which encompasses them in an overall transnational field cannot be found. By presenting a multi-dimensional refinement of the mixed embeddedness and transposing it to the transnational field, we provide scholarship with an analytical framework for transnational migrant entrepreneurship. It allows comparative analysis of entrepreneurial environments and could be prospectively even more broadly applied in the field of migrant entrepreneurship in other contexts. This model can contribute to a clearer understanding of contextual influences and lead to precise policy recommendations on supports required for entrepreneurial activities, in particular at "the crucial mesolevel". The framework can be used to inform policy-makers on the multiple influences of institutional (policy) support based at the meso level, and of its social and economic aspects, aiming to encourage and foster transnationalization activities of migrant entrepreneurs. Policy-makers need data but also analytical tools to think their actions, which, we as academics, can provide. Such a differentiated analysis of migrant entrepreneurship which accounts not only for the multi-levels, but also for the multi-dimensionality of mixed embeddedness, also allows more precise pinpointing of specific policy recommendations. As the findings have clearly shown, transnational entrepreneurs can be well embedded at the meso-level in the social and economic fields, yet support policies are not reaching them properly at the meso-level. By targeting specific elements of the social and economic fields, such as connecting to ethnic communities as intermediaries for the inclusion of migrant entrepreneurs into wider local business networks (social dimension) or promoting specific funding institutions for cross-border trade to actors of the migration industries (economic dimension), policy-makers (located in the political dimension) could succeed in supporting transnational migrant entrepreneurship. This proposed model of multi-dimensional mixed embeddedness is thus useful for researchers and policy makers alike to better grasp the overall contexts of migrant entrepreneurship to develop effective support measures. It is finally useful to encourage students to explore the role of contextual conditions on (transnational) business activities. The model and a similar argument can be used to look at other trade blocs or other contexts, including in the Global South, for which more research on the conditions of transnational entrepreneurship can be conducted.