User blog comment:B214/Volume 17 spoilers./@comment-117.193.172.96-20140220062652/@comment-1359322-20140220073809

The Gremory already has sufficient money. Plus the sponsor for the Oppai Dragon show is the Gremory. Issei's money came from the Gremory's sponsorship on Oppai Dragon show and merchandise not the other way around.