The U.S. dollar zigzagged to a session high and back on Wednesday after the Federal Reserve disappointed investors expecting a shift toward more purchases of longer-dated bonds, while investors kept their focus on Bitcoin, which smashed through $20,000 for the first time.

The dollar hovered near two-year lows on Monday as riskier currencies got a boost from progress on COVID-19 vaccines and the possibility of a U.S. coronavirus relief plan.

The greenback bounced on safe haven buying on Friday as risk appetite fell due to concerns over delayed U.S. fiscal stimulus amid a surge in COVID-19 cases and the increasing likelihood that Britain will exit the European Union without a deal.

The euro rose on Thursday after the European Central Bank disappointed some investors looking for a larger stimulus boost, while sterling fell as the prospect of a no-deal Brexit appeared more likely.

The pound extended its losses against the dollar and the euro on Thursday, and one-week implied volatility gauges rose to their highest since March, as market participants became more cautious about the risk of a no-deal Brexit.

The British pound fell 0.5% in early Asian trade on Thursday after British Prime Minister Boris Johnson and European Commission President Ursula von der Leyen agreed they have until Sunday to take a "firm decision" about the future of trade talks.

The dollar rose for a fourth straight session on Wednesday, as selling momentum eased with stocks under pressure, but positive vaccine news and prospects of more U.S. fiscal stimulus next year should temper gains on the greenback.

Sterling rose against a broadly weaker dollar on Wednesday, but later pared some of its gains after British Prime Minister Boris Johnson signalled intransigence in Brexit trade talks as he headed to Brussels for dinner with the president of the European Commission.

The dollar edged higher on Tuesday in choppy trading, taking a breather from a sell-off that took it to its lowest level in more than 2-1/2 years last week, while sterling slipped as investors awaited the outcome of Brexit trade-deal talks.

The British pound erased earlier losses and briefly popped into positive territory in a volatile trading session on Tuesday after Britain said it had clinched a deal with the European Union over how to manage the Ireland-Northern Ireland border.

The dollar slid against most currencies on Monday in choppy trading, as investors looked past the surge in coronavirus cases and ahead to a possible new COVID-19 U.S. stimulus deal and vaccines to fight the pandemic.

The pound fell to six-week lows versus the euro on Monday, also dropping against the dollar, as last-ditch trade talks between Britain and the European Union resumed in Brussels and investors re-evaluated the risk of a no-deal Brexit.

The U.S. dollar rose from 2-1/2-year lows on Friday, as European Union and British negotiators paused talks for a post-Brexit trade deal, weighing on sterling, though the greenback still posted its worst week in a month after investors shrugged off a weaker-than-expected...

Sterling fell from a 2-1/2-year high versus the dollar on Friday after Britain and the European Union failed to strike a trade agreement, with discussions paused so negotiators could talk to politicians for guidance.

Sterling could be in for a bumpy December as Britain's informal membership of the European Union expires at the end of the year and the two sides have yet to agree on their future trading relationship, a Reuters poll found.

The dollar plunged on Thursday to its weakest level in more than 2-1/2 years, while the euro gained, as signs of progress toward U.S. fiscal stimulus and optimism about COVID-19 vaccines kept investors upbeat.

The British pound climbed to a one-year high near $1.35 on Thursday as a U.S. dollar selloff gathered momentum, but growing unease about a Brexit trade deal prompted investors to take protective action in the derivative markets.

The dollar sank to a fresh 2-1/2-year low in choppy trading on Wednesday, weighed down by expectations of further fiscal stimulus for the United States.

Sterling fell to a one-month low against the euro and also dipped momentarily below $1.33 on Wednesday as Britain and the European Union quickly approached a make-or-break moment in trade talks, with many investors doubting a deal will be reached.

The dollar fell on Tuesday to its lowest level in more than 2-1/2 years, as investors' appetite for risk increased on prospects of further fiscal stimulus from the United States as well as expectations of a solid global recovery.