Shares of Rivian Automotive Inc. briefly fell below their IPO price on Thursday in a broader selloff among electric vehicle (EV) makers as the race for market share intensifies with legacy companies ramping up EV production. Rivian shares fell as much as 16.5 percent to $75.13, slipping below the debut price of $78 for the first time. They pared losses and were trading down 5 percent at $85.66 in mid-day trading. Other EV makers Tesla Inc., Lucid Group and Fisker also lost ground, with valuation of high-flying tech sector coming under pressure against the backdrop of the Federal Reserve’s hawkish signals. The slide in Rivian shares comes a day after one of its biggest investors, Amazon.com Inc., teamed up with carmaker Stellantis NV. They will develop cars and trucks with Amazon software and deploy electric vans made by Stellantis on Amazon’s delivery network. “Amazon has invested a lot of money …