NEW YORK (Reuters) - The U.S. interest rate that the Federal Reserve targets to achieve its monetary policy touched its highest level on Friday since the height of the global credit crisis, following Britain's stunning vote to leave the European Union.

Thursday's referendum on Britain's membership in the economic bloc threw financial markets into turmoil as investors fretted about the global fallout, including on the British banks.

The average, or effective, fed funds rate <USONFFE=> was 0.40 percent, up from 0.39 percent on Thursday. It traded in a range of 0.38 percent to 0.56 percent, with $70 billion in this type of interbank loan changing hands, the New York Federal Reserve said on Monday.

On Thursday, the trading range was 0.37 percent to 0.56 percent, with $71 billion changing hands.

Meanwhile, the Fed's overnight bank funding rate was 0.40 percent on Friday, up from 0.39 percent on Thursday.

This rate, calculated using fed funds and certain Eurodollar transactions, is intended as a broader measure of unsecured borrowing in U.S. money markets.

These transactions changed hands at 0.05 percent to 0.47 percent on Friday, compared with Thursday's range of 0.27 percent to 0.47 percent.

The New York Fed said Friday's rate was based on $248 billion worth of loans, compared with $244 billion on Thursday.

(Reporting by Richard Leong; Editing by Lisa Von Ahn)