FED BUYS ONE BILLION DLRS OF BILLS FOR CUSTOMER The Federal Reserve is buying one billion dlrs of Treasury bills for customer account for delivery today, a spokesman for the bank said. Fed funds were trading at 6-3/16 pct at the time of the purchase, which came several hours before the Fed normally transacts business for its customers. Economists said the purchase was almost certainly related to the investment of proceeds from recent central bank intervention in the foreign exchanges. The Bank of Japan alone is estimated to have bought about six billion dlrs in March in a bid to prop up the dollar.