Shares of Coinbase Global Inc. COIN, +0.26% dropped 3.4% in premarket trading Friday, putting them on course for a fifth straight decline, as a selloff in bitcoin BTCUSD, -2.14% toward a 7-week low weighed on the recently public cryptocurrency exchange. The stock has dropped 14.2% over the past four sessions, and has tumbled 23.0% since its first trade of $381.00 on April 14. Meanwhile, bitcoin slumped 4.6% early Friday, and has dropped 19.8% this week and has lost 24.1% from the an all-time intraday high reached on April 14, according to FactSet data. The S&P 500 SPX, +1.21% has lost 1.2% this week, and futures ES00, +1.16% are up 0.1% ahead of Friday’s open.