NEW YORK (CNN/Money) - If you were just looking at the bond market, you'd think the United States has suddenly fallen into a world of hurt.

Since Monday, the Treasury market has rallied hard, dropping the yield on the 10-year note from 3.89 percent to 3.64 percent. Such flights to the safety of bonds tend to happen in the most uncertain of times -- like when stocks fell into that sharp downdraft back in October and when the jitters before the Iraq war were at their peak.

Stock investors watching that drop in bond yields have got to be nervous. It tests their belief that the economy and earnings are on the verge of lifting into a robust recovery. The knowledge that Treasury traders are way more focused on the economy than stock traders just increases the worry.

It's true that the Treasury market tends to play Snidely Whiplash to the equity market's Dudley Do-Right, with bond investors hoping for a weak economy while stock-types hope things will get better. Ask bond traders what the chances are for the kind of economic rebound the stock market, in its most recent rally, seems to have envisioned, and the odds they give you will be very slim.

But there are other factors at play here. The big catalyst for the drop in Treasury yields over the past few days was, of course, Tuesday's Federal Open Market Committee meeting, where the Fed openly worried in its statement over the possibility that inflation could go to low -- in other words, that the economy could enter a deflationary environment.

That in itself shouldn't (though it may) have sparked a run into bonds. The possibility of deflation was already there. That the Fed admitted it, suggests the Fed is ready to fight tooth and nail to keep it from happening. If anything, what the Fed said lowers the chances of deflation.

No, it's the way the Fed may fight deflation that has investors jumping into bonds. The Fed's statement suggested that it may, in order to fight against deflation, create an inflation target -- an idea that has long been held by new Fed governor Ben Bernanke.

Inflation-targeting isn't the only idea that Bernanke has come up with, however. In a November speech he suggested that to prevent deflation the Fed might, in an effort to lower borrowing costs and encourage investment, purchase Treasurys. Since the Fed appears to be paying attention to Bernanke, Treasury investors are wondering whether the bank might start buying.

And they are buying ahead of it.  

-- Justin Lahart is a senior writer at CNN/Money covering markets and investing.