Mega-cap growth firms Amazon.com AMZN.O, Microsoft Corp MSFT.O, Apple Inc AAPL.O and Tesla Inc TSLA.O slid between 2.5% and 6%, also pressured by rising U.S. Treasury yields. By Shreyashi Sanyal and Sruthi Shankar June 16 (Reuters) - U.S. stock indexes tumbled on Thursday, with growth shares bearing the brunt of the selloff, after the Federal Reserve's largest rate increase since 1994 to combat decades-high inflation fanned worries of a recession. The benchmark index snapped a five-session losing streak on Wednesday after the Fed's 75 basis point rate increase matched market expectations.