Coinbase CEO Brian Armstrong ranked 8th among the top 60 executives of S&P 500 companies in terms of the size of insider sales last year, according to OpenInsider, a website that discloses insider trading information in the US stock market. Armstrong sold $636 million worth of Coinbase shares (NASDAQ: COIN), trailing behind MicroStrategy founder Michael Saylor, who sold $410.8 million and ranked 13th, but far ahead of Amazon founder Jeff Bezos, who ranked first with sales of about $13.4 billion.