A new search for the gravitational lens effects of a significant cosmological density of supermassive compact objects (SCOs) on gamma-ray bursts (GRBs) has yielded a null result. We inspected the timing data of 774 BATSE-triggered GRBs for evidence of millilensing: repeated peaks similar in light-curve shape and spectra. Our null detection leads us to conclude that, in all candidate universes simulated, ${\Omega }_{\mathrm{SCO}}<0.1\mathrm{}$ is favored for SCO masses in the range ${10}^5<M_{\mathrm{SCO}}/M_{\odot }<{10}^9$, while in some universes and mass ranges the density limits are as much as 10 times lower. Therefore, a cosmologically significant population of SCOs near globular cluster mass did not come out of the primordial universe or condense at recombination.

• Received 18 October 1999

DOI:https://doi.org/10.1103/PhysRevLett.86.580