(Bloomberg) -- They were hailed as Silicon Valley’s answer to the traditional Wall Street IPO. A way for founders of hot tech startups to sidestep the hefty fees and the millions of dollars potentially left on the table when bankers took them public. A string of high-profile direct listings, including Squarespace Inc. and ZipRecruiter Inc. flopped recently, but Coinbase Global Inc. was particularly notable. Since going public in April with plenty of fanfare, the cryptocurrency exchange has slumped, even dropping below its so-called reference price, a level skeptics have called an artificially low bar to pass.