MICHELE NORRIS, host: There is a lot of speculations about just how much all of these downgrades are weighing on stock markets and whether they will continue to ripple through the economy.
But as NPR's Yuki Noguchi explains, there are systemic reasons why ratings matter less now than they used to.
YUKI NOGUCHI: Conventional wisdom said, a U.S. downgrade would make Treasuries riskier. It would make yields or interest rates rise. In fact, bond markets did the opposite. In spite of S&P's higher risk assessment of U.S. debt, demand for Treasuries kept flooding in.
UNIDENTIFIED MAN: It really is a breathtaking ride. We've continued to move into the lower zone of...
NOGUCHI: The easy explanation for this is that Europe is consumed with its own debt crisis, which makes the U.S. still the safer bet. True, but the significance of ratings has also changed.
KENT SMETTERS: Ratings are becoming less important across the board.
NOGUCHI: Kent Smetters is a professor at the Wharton School. He says ratings were more powerful just a few years ago. They amplified the boom, and then the bust of mortgage securities.
SMETTERS: The ratings really played a key role in getting a lot of capital into the mortgage market. That has obviously retrenched quite a bit. Insurance companies today do not put nearly as much capital to work based on ratings alone.
NOGUCHI: The Dodd-Frank financial reform bill passed a year ago is also responsible for taking the importance of ratings down a peg. The law requires banks and insurance companies, for example, to hold more capital based on the risks of their assets. The riskier their assets, the more money they have to keep on hand.
In the past, regulators measured that risk using ratings like S&P and Moody's. But the new law, once fully implemented, will change that. Risks of all sorts of securities will be measured in other ways. For example, internal assessments, but they won't be pegged to a ratings agency's verdict.
The Federal Reserve is underscoring the move away from ratings agencies. Soon after S&P announced its downgrade on Friday, the Fed said it would not require banks and other institutions to hold more capital because of the change. Ratings used to also guide a lot of institutional investors, but not so much anymore.
KEITH BRAINARD: I can foresee few, if any, instances in which pension funds would need to rush to sell any assets as a result of the downgrade of the United States Treasury debt.
NOGUCHI: Keith Brainard is research director for the National Association of State Retirement Administrators. He says that over the past two decades, pensions have changed the language of their investment guidelines to rely less on ratings.
Analysts point to other reasons people have lost faith in ratings in recent years. They point to a 2002 downgrade that had no impact on Japan. They say ratings agencies acted long after bond markets had digested state budget problems in California or Illinois.
KAREN PETROU: The markets do not believe that S&P is right.
NOGUCHI: Karen Petrou is managing director of Federal Financial Analytics. She says, if anything, people are jumping from stock markets into Treasuries because of their relative safety.
PETROU: The alternative to Treasuries is the mattress.
NOGUCHI: Petrou says she believes investors over the weekend got spooked that stock markets would fall, and that's what triggered a stock sell-off, not the downgrade itself.
PETROU: The markets are so volatile right now that forecasting any long-term impact on mortgage rates or car interest rates, I think is premature.
NOGUCHI: If the economy is a plane, she says, the ratings system is the device that measures altitude. And it's broken, but so is the landing gear, and the engine isn't working either.
Yuki Noguchi, NPR News, Washington.