Reserve Lifts Its Bank Loan Rate; Stocks Off, Citibank Raises.Prime
US Fed Reserve Bd approves increase in discount rate, from 6% to 6 1/2%; cites current disorder in currency exch mkts resulting from decline of dollar; apparently is 1st time in recent yrs that bd has used discount rate as device to influence currency mkts; analysts interpret decision as symbolic gesture to underscore determination to support dollar against foreign currencies (M)