Coinbase CEO Brian Armstrong floated the idea of creating a crypto index fund, calling it the "Coinbase 500" during an earnings call on Thursday. He said it would help retail products grow in the crypto space. Although Coinbase's second-quarter trading volume was $226 billion, down from $312 billion in the previous quarter, it exceeded analysts' expectations. Armstrong noted that the launch of a crypto index faces regulatory hurdles and requires a more friendly policy environment.