The Dow Jones Industrials (DJINDICES:^DJI) managed to overcome early losses and gain five points as of 12:30 p.m. EST, continuing the impressive rebound that has taken the average up 840 points from its lows earlier this month. Yet the most surprising thing about the Dow's rebound is that it hasn't come at the expense of the bond market, as the 10-Year Treasury Yield (TREASURY: TC10Y) hasn't risen nearly as much as investors expected.

Backward thinking
Coming into 2014, most investors believed that interest rates would steadily rise as a result of the Federal Reserve's drawdown of its quantitative-easing bond-buying activity. With 10-year rates having risen by half a percentage point between late October and the end of 2013, betting on a continuing trend seemed like a reasonable play.

Yet 2014's market correction led to a big turnaround for bonds. Yields plunged from 3% to 2.6% in January, leading bond prices to rise and giving bond investors gains at the same time that their stock-investor counterparts were suffering troubling losses.

As the Dow bounced back from its January losses, though, it would have been natural for bonds to return to their late 2013 levels. Yet at least so far, that hasn't happened, and even as the Dow inches upward today, 10-year yields are on the decline to hit 2.7% -- a tiny move compared to the magnitude of the recovery in the stock market.

What's behind bond yields?
The relative stability of bond yields points to investor uncertainty about the status of the economy. At least so far, stock investors have largely ignored economic data suggesting slowing growth in the U.S., blaming the weather and other temporary impacts and projecting a return to normal conditions once winter ends. That determination is a big part of why stocks have continued to climb even as much-watched indicators such as housing starts and sales would ordinarily raise much larger concerns.

At the same time, though, bonds appear to be giving those economic measures more credence. For instance, today's drop in bond yields came after the latest consumer-confidence reading fell more than economists had expected. Despite the Fed's determination to keep withdrawing from its quantitative easing strategies, bond investors believe the central bank won't want to sabotage ongoing efforts to return the economy to a more normal footing.

How to play low rates
For now, the Dow's biggest winners from low interest rates are likely big banks JPMorgan Chase (NYSE:JPM) and Goldman Sachs (NYSE:GS). Both have extensive exposure to bonds, both directly and in the business they do for their respective clients. A huge rise in bond yields would be dangerous for the banks, but even what could prove to be a temporary return of low rates could lead to a surge in activity among borrowers to lock in attractive financing one final time.

In general, investors shouldn't expect both the stock market to rise and interest rates to keep falling. At some point, bond yields and stocks will likely disengage from each other. So far, though, that largely hasn't happened, and that makes for the most surprising winner in the Dow's rebound this month.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.