Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

Stocks are moving lower today as investors come to the realization that the Federal Reserve will slow its $85 billion-per-month bond-buying program something this fall. The big result of the market's coming to grips with tapering was a 0.1% rise in the 10-year Treasury rate to more than 2.7%. This is the benchmark rate used to set mortgage rates, and as it rises, homes become less and less affordable. It should be no surprise, then, that the Mortgage Bankers Association reported that mortgage applications dropped 4.7% last week, while refinancing dropped 4.4% -- a trend that will likely continue this week and in months ahead.

Corporate borrowing costs also go up when interest rates rise, which can crimp corporate profits. That's one reason stocks are selling off today, with the Dow Jones Industrial Average (DJINDICES:^DJI) falling 0.58% and the S&P 500 (SNPINDEX:^GSPC) dropping 0.36% as of 3:25 p.m. EDT.

One of the stocks dragging the most on the Dow today is Boeing (NYSE:BA) after yet another 787 Dreamliner safety concern was revealed. ANA Holdings, which is the biggest 787 operator, said it discovered wiring defects in the engine fire suppression system today. The problem was found on three aircraft, and it looks like all three will be fixed by the end of the day. 

The company is counting on the 787 Dreamliner to be its next growth engine, and so far in 2013 it has done nothing but cause headaches for everyone at the company. This isn't a deal breaker for Boeing, and most will chalk it up as a normal bug on a new aircraft, but so far the bugs just keep on coming. For today the stock is sliding, but Boeing is up 41% so far this year, so investors don't seem too concerned about the glitches overall.

Bank of America (NYSE:BAC) is one stock bucking the downtrend today, climbing 1% today. B of A is one of the biggest mortgage companies in the world, and rising long-term rates can actually have a positive impact on that business. Banks borrow at short-term rates and loan out at long-term rates, so when rates rise, their spreads increase, and so do profits. Don't expect mortgage applications to grow as rates rise, but each loan Bank of America originates will be more profitable to the company.

Fool contributor Travis Hoium has no position in any stocks mentioned. The Motley Fool recommends Bank of America. The Motley Fool owns shares of Bank of America. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.