GCAP - GAIN Capital May OTC trading volume declines 4.7% from April June, 09 2020 08:42 AM GAIN Capital Holdings Inc. GAIN Capital Holdings (NYSE:GCAP) OTC trading volume of $179.3B in May falls 4.7% from April and 0.6% from May 2019.More news on: GAIN Capital Holdings, Inc., Financial stocks news, Read more ...