In its latest effort to try and stimulate the U.S. economy, the Federal Reserve cut its key interest rate to a range of between zero percent and 0.25%, and said it expects to keep rates near that unprecedented low level for some time to come.

The central bank typically sets a specific target for its federal funds rate instead of a range. The rate had previously been at 1% and this marks the first time the Fed has cut rates below 1%. Most investors were expecting the Fed to cut rates to either 0.25% or 0.5%.

The federal funds rate is an overnight lending rate used as a benchmark to set rates for a variety of loans, including adjustable rate mortgages, credit cards, home equity lines of credit and business loans. This marks the tenth time it has cut rates in the last 15 months.

Several banks announced they were lowering their prime rate to 3.25% in light of the Fed's decision. Typically, the prime rate is 3 percentage points higher than the fed funds rate. It was 4% before Tuesday's rate cut.

Despite the dramatic nature of the Fed's move, some economists questioned whether it will have much effect on the economy. They said the problem for consumers and businesses right now is not the cost of borrowing, but the availability of credit and the weaker economic fundamentals.

"Lowering rates to this level is purely a psychological move made to send the message that the Fed is committed to righting the sinking economic ship," said Rich Yamarone, director of economic research at Argus Research. He noted the previous rate cuts did little to stop home and auto sales from plunging.