NEW YORK (CNN/Money) - People keep on calling the top on the Treasury market and if they were wrong the first time, they just call it again.

And yet, defying all expectations, bonds just keep on rolling. Just this year the fury of the rally in bonds has pushed the yield on the 10-year Treasury down from 3.82 percent to 3.3 percent. The Lehman Brothers Long Bond index is up about 10 percent this year -- just a bit less than stocks, and without all the bear market pain of the past.

The move just doesn't make sense to a lot of Wall Streeters, who reckon that something else must be afoot. And many of them think they've smoked out what's going on: In an effort to keep long rates low, the Federal Reserve is intervening massively in the Treasury market.

Don't laugh. Lots of otherwise seemingly reasonable people have been saying this. Okay, laugh if you must -- and if you're one of the folks who really think the Fed is covertly intervening in the Treasury market, realize that the people laughing are a) really laughing with you, and b) all part of the conspiracy.

"Way too many people have been saying this," said Brian Reynolds, fixed income strategist at Kirlin Securities (and clearly a member of the conspiracy). "I'm even getting people asking if the Fed is buying stocks, which is just too weird."

It's true that the Fed does own some Treasurys to offset its liabilities, and that it occasionally goes into the market, in what is called a coupon pass, to buy more. This year it's added about $32 billion in Treasurys to its balances. For the same period last year, it had added $36 billion. All this information is freely available on the Federal Reserve Web site.

So how did the conspiracy get started? Mostly it's thanks to the guy who is fast becoming everybody's favorite Fed governor, Ben Bernanke. In an oft-perused speech he gave in November, "Deflation: Making Sure 'It' Doesn't Happen Here," Bernanke noted that the Fed potentially has more weapons at its disposal to revive the economy than just setting the funds rate. One of them was, you guessed it, buying Treasurys.

The Bernanke speech is credited with much of the run in Treasurys -- some have even termed what's going on the "Bernanke put." It's done exactly what it was supposed to do. For instance, fueling a bunch of conspiracy theories about how the Fed is buying Treasurys and thus keeping long-term rates nice and low. Who needs to use unconventional tactics to push rates lower when the market does the work for you?

If it really did come to the point where the Fed felt it needed to intervene in Treasurys, it would certainly want to make it known. Otherwise, within the massive Treasury market, it would have very little impact. Think of how effective the massive currency intervention that U.S. Treasury Secretary Robert Rubin crafted in June of 1998 was at stopping the yen's slide. It worked because it was exquisitely timed, and because it only took currency traders a few moments to know damn well what was going on.

"I'm not against conspiracy theories as a whole, but they have to be at least somewhat credible," said Credit Suisse First Boston bond strategist Mike Cloherty. "I guess that now that the 'X Files' is off the air you need to have this stuff to fill the void."