2. The interest rates YOU and YOUR EMPLOYER pay will go up. Basic credit facilities -- like mortgages, student loans and credit cards -- are all at least loosely tied to the rates the government pays. A half a percent increase in mortgage rates could increase the total cost of the average traditional mortgage by $19K (on a $172K home). Businesses would have to spend more money to finance expansions. Costs for borrowed money goes up, effectively raising the price of anything you're not paying for with cash.
3. Needless to say, increasing costs for consumers and businesses tends to slow their economic activity. Some estimates put a downgrade like this as likely to shave 1 percent off GDP. This slowing certainly increases the risks that the U.S. will have a second dip into recession. It also means less tax revenue, so the potential for additional debt increases.
4. As the economy slows, expect the stock market to react. After all, investors buy shares to get a piece of growing profits. A slowing economy means profits grow less rapidly or go down. The relative value of a share of anything will go down. Some experts predict a downgrade could force stocks to sell-off by 6 percent to 10 percent in short order. That's another 1,100 points on the Dow.
5. A slowdown in economic activity also means less demand for workers. The non-partisan group Third Way has published estimates that a simple 0.5 percent increase in interest rates could erase more than 640,000 jobs.