A longstanding problem for hedge funds has been the limited number of companies that have sufficient amount of publicly traded stock to accommodate the appetite of hedge funds with billions of dollars to invest. The result is "herding" where many large hedge funds end up with similar positions: i.e., a concentration of assets in a small number of stocks. Additionally, these stocks make up a significant component of the S&P 500 which causes the heavily exposed hedge funds to show performance that mimics the S&P 500 as well as each other.
Facebook stock decline hits hedge funds hard
SEC continues to reject Bitcoin ETF proposals because the proposals are not consistent with the Exchange Act Section 6(b)(5) and its requirement that a national securities exchange's rules "be designed to prevent fraudulent and manipulative acts and practices." https://www.coindesk.com/sec-rejects-7-bitcoin-etf-proposals/
Three trends portend a possible bubble collapse in the debt market. First, the extension of credit has become more lax; Second, the Fed has stopped providing liquidity under quantitative easing; third, Low asset returns has caused investors to overpay for risky assets.