US Dollar Index

The US Dollar Index (USDX or DXY) measures the dollar against a weighted basket of six currencies: the euro, Japanese yen, British pound, Canadian dollar, Swedish krona and Swiss franc. It started at 100 in 1973, so a reading of 105 means the dollar is about 5% stronger against that basket than it was then.

It is the quickest way to see whether the dollar is broadly rising or falling. The catch: the euro makes up more than half the basket, so the index is heavily influenced by EUR/USD and ignores big partners like China and Mexico.