The dollar experienced its biggest one-day drop in 13 years Wednesday as the U.S. Federal Reserve cut a key interest rate by half a percent.

Between Tuesday and Wednesday, the cost of a euro jumped 3.75 cents in midday trading, according to the Federal Reserve Bank of New York.

The British pound traded 7.07 cents higher at noon Wednesday than it had a day earlier.

The Fed’s move also caused the U.S. Dollar Index, a measure of the value of the dollar relative to six other major currencies, to drop by the biggest margin in 23 years.

On-base exchange rates in Europe jumped in response Friday. The euro, which cost $1.3099 Thursday through on-base banks, jumped to $1.347 and the British pound, which cost $1.65, rose to $1.71 on Friday.

The dollar has been strengthening against the euro and pound since July, and had fallen to near $1.24 per euro earlier in the week as borrowers paid back loans to the U.S., strengthening the currency. The Fed’s move to lower a key interest rate spurred new borrowing, causing the dollar to plunge.

A strong dollar generally makes it easier for overseas Americans who earn dollars to make purchases on the local economy, and mostly benefits those who don’t receive cost-of-living allowances. At the same time, the strong dollar makes it harder for American manufacturers to sell their goods overseas.