Gains in European stocks helped sterling and the dollar climb against safe-haven currencies like the yen on Thursday.
Sterling tumbled to a seven-year low on Wednesday on heightened fears of a possible British exit from the European Union.
The yen and Swiss franc rallied across the board on Tuesday as a recent rebound in stocks and crude oil faded.
Currency traders have been circling exchange rates this week, with expectations high that political divisions could lead to further opportunities.
The dollar rose to a three-week high, bolstered by gains in oil and stocks as well as losses in sterling and euro.
The yen rose against the euro and dollar on Friday after yet another downbeat session for oil prices and stock markets worldwide.
The dollar rose against most currencies, bolstered by an increase in risk appetite amid a continued recovery in oil prices.
The U.S. dollar fell below 114 yen after the Federal Reserve released the minutes from its January meeting.
The dollar rose against most major currencies on Tuesday as an agreement between the world's top oil producers increased investors' appetite for risk.
The euro and yen weakened Monday after a warning on volatile currency markets and huge gains from China's yuan helped settle financial nerves.
The dollar index rose on Friday after positive consumer spending data suggested the Fed may raise interest rates this year.
But as central bank's appear to be running out of options, their moves to weaken their currencies have become increasingly unsuccessful.
The dollar fell to a 15-month low against the yen on Thursday, on track for its worst week against the yen since 2008.
The dollar fell to a 15-month low against the yen on Wednesday as investors packed into the safe-haven Japanese yen.
The dollar tumbled to a four-month low on Tuesday as growing fears of a global slowdown pushed investors to safe-haven currencies.
The yen surged by half a percent against the dollar as worry over Europe's banks drove capital to the safety currecny.
The dollar rebounded on Friday after data showed a pickup in U.S. wages, suggesting rates hikes are more likely to happen in 2016.
The dollar was on the defensive after a collapse in hopes of a further rise in U.S. interest rates this year drove its biggest daily fall.
The yen rose on Wednesday as weaker stock markets in Europe spurred investors to buy safe haven assets.
The U.S. dollar fell against the euro and yen on Tuesday after a drop in oil prices suggested U.S. inflation would stay low.