FED BUYS 550 MLN DLRS OF BILLS FOR CUSTOMER

  The Federal Reserve bought about 550
  mln dlrs of U.S. Treasury bills for a customer, a spokeswoman
  said.
      She said the Fed bought bills maturing from May through
  September 24 for regular delivery tomorrow.
      Federal funds were trading at 6-3/16 pct when the Fed
  announced the operation.
  

