It's been almost two years since the Federal Reserve set interest rates to the current near-zero levels. The Fed has kept the target range for the federal funds rate (the interest rate at which banks lend to each other) between zero and 0.25 percent since December 2008 and has, since March 2009, repeated its pledge to keep rates low for an "extended period." That's a signal that it doesn't plan on changing its tune any time soon, experts say.

On top of record-low interest rates, the Fed has also pursued a strategy called quantitative easing, which involves buying up government securities like treasuries to push interest rates even lower in hopes of stimulating more lending to spur economic activity. The first round of quantitative easing started in 2008, and many experts believe the Fed will announce plans to begin another asset-buying program (referred to as QE2) in its next rate announcement in November. Here are four reasons why another round of asset purchases could be problematic:

Savers are hurting. The yield on the 10-year treasury note has hovered around 2.5 percent for most of the latter half of 2010. Historically, rates have been much higher. In mid-2007, when economic growth was much more robust and demand for treasuries was much lower, 10-year treasuries were yielding as much as 5 percent. Many older investors depend on the income they receive from their investments in high-quality bonds like treasuries, and faced with paltry treasury yields, many are considering whether they should take on more risk. "It forces people out the risk spectrum in order to get yield, and a lot of people that are forced out the risk spectrum shouldn't be forced out the risk spectrum," says Liz Ann Sonders, chief investment strategist at Charles Schwab. Rates can only move higher, and when they do, investors that have moved farther down the duration scale (a measure of interest-rate sensitivity) will feel the pain. When interest rates rise, the price of bonds falls--and longer duration bonds will be hit harder than others.