First, even if you don’t trade currencies (and most people don’t), they can have a big influence on the stock market. Moves in the foreign-exchange markets impact companies operating outside the U.S. They can also move commodity prices and related stocks.
The Market Vectors Semiconductor ETF (SMH) is up about 7 percent in the last week, making it the best-performing major fund in the entire market. Its sharp gains so far in April also put it on pace for its best month in over a decade.