In 2013, the following 11 collectors (out of 200) had some form of photography called out in their collection description, often one of many artwork types in a larger list:
Joop van Caldenborgh
Ella Fontanals Cisneros
Danielle and David Ganek
Alison and Peter W. KleinThomas H. Lee and Ann Tenenbaum
Heather and Tony PodestaLisa S. and John A. Pritzker
Aby J. Rosen
Compared to similar lists from prior years, there is remarkable consistency in the names above; most have been on this list for plenty of consecutive years. Of course, this short photo-focused list is a little deceiving, in that roughly 85% of the names on the complete list of 200 collectors have "modern", "contemporary", or "emerging" art in their bios, so many of them likely collect some photography as a subset of their larger efforts, but haven't had it called out specifically as an interest; in fact, there may be other names with broad collection descriptions that may indeed own more photography than some of the names above. More generally, it would be fascinating to know how many of the complete list of 200 own at least one photograph; my guess is that it's meaningfully more than 50%, which points to a much broader rate of inclusion than the data here explicitly shows. All in, this annual list is always an entertaining barometer of what the most active among us are collecting, allowing us to sketch out a faint picture of the machinations at the top end of the market.