A new species is prowling America’s most obscure industry conferences: the data hunter.

Erik Haines, head of data and analytics at New York-based Guidepoint Global LLC, trawls the globe for meaningful data to sell to hedge-fund clients. One of his best strategies is to attend the most seemingly mundane gatherings, such as the Association for Healthcare Resource & Materials Management conference in San Diego last year, and the National Industrial Transportation League event in New Orleans.

“I...