It's still too early to measure the entire effect of Japan's earthquake on the U.S. economy. A few things, however, are all but certain.
Companies that export goods and services to Japan will not necessarily be badly hurt. U.S. goods exported to Japan totaled $51 billion in 2009, according to the Office of the U.S. Trade Representative.
The top exports to Japan were optical equipment, aircraft, machinery, and cereal. Japan's need for machinery and cereal may rise -- at least short term -- as the country rebuilds infrastructure and deals with food shortages.
U.S. goods imported from Japan totaled $96 billion in 2009. Japan's largest export to the U.S. is cars. U.S. manufacturers like Ford Motor (F) and GM (GM) may get short-term benefits from a slowdown in exports by Toyota Motor (TM), Honda (HMC), and Nissan.
Japan may also be badly hurt as foreign investment falls on concerns about risks. There will be a migration from Japanese equities and bonds. Some of this capital may seek the safe haven of the U.S. equity markets and treasuries. The value of American stocks could actually rise for a time. This could be particularly true for shares of companies that have powerful and direct competition in Japan, like Caterpillar (CAT) and Eastman Kodak (EK).
There is also likely to be upward pressure on the prices of consumer electronics in the U.S. due to shortages of components made in Japan, such as flash memory. There may also be disruptions in the supply of parts for devices like the Apple (AAPL) iPhone and iPad.
Expectations that production problems for such a major U.S. trade partner as Japan would benefit American companies may not be met.