** Shares of U.S. exchange operators CME Group CME.O, Intercontinental Exchange ICE.N, and Cboe Global Markets CBOE.Z extend selloff as investors weigh fallout of approval for perpetual crypto futures

** CBOE down 7%, CME down 4.4% and ICE down 4%

** The approval has sparked concerns that U.S. exchanges could be hurt if such vehicles get extended across asset classes such as equity products

** Investors in U.S. exchanges are nervous that products with significant retail participation are at risk of losing market share to new competitors with perpetual futures contracts, analysts have said

** But analysts see the competitive risk as manageable for U.S. exchanges given fundamental product differences and structural advantages

** As of last close, CME and ICE down 5.6% and 10.5% YTD, respectively, while Cboe has gained 19.9%