Top: Distribution of BH and donor masses in ULX systems, weighting our models to the metallicity distribution of Langer & Norman (2006) at redshift z = 0. Middle: Distribution of mass ratios using the same metallicity distribution. Bottom: Distribution of orbital periods using the same metallicity distribution. Donor masses and orbital periods are separated between Case A and Case B systems; furthermore, Case A systems are separated between donors that are hydrogen-poor or hydrogen-rich at their surfaces.