Final answer:
The targeted interest rate for open market operations in the U.S. is the federal funds rate, used by the Federal Reserve to guide monetary policy.
Step-by-step explanation:
The specific interest rate targeted in open market operations in the United States is the federal funds rate. This rate is significant because it is the rate at which commercial banks borrow and lend their excess reserves to each other overnight.
The Federal Reserve, or 'the Fed,' uses open market operations as its primary monetary policy tool, where it buys or sells U.S. Treasury bonds to adjust the money supply and, hence, the federal funds rate. This short term interest rate is a key indicator of the credit conditions in the financial markets and is closely monitored as it influences various other interest rates.