** Shares of U.S. derivatives exchange operators fall after Federal Reserve cuts interest rates by half a percentage point
** CME CME.O and Cboe Global CBOE.Z down ~1% each
** While lower rates encourage IPOs and boost trading, they also reduce demand for hedging products such as derivatives
** Nasdaq NDAQ.O inches up 0.5%, while NYSE-owner Intercontinental Exchange ICE.N down 0.4%
** Meanwhile, Wall Street's main indexes extended gains .N
(Reporting by Niket Nishant in Bengaluru)