US stocks finished firmly in the green on Thursday after President Donald Trump unveiled a "breakthrough" trade agreement with the United Kingdom.

The deal reduces tariffs on British cars, steel and aluminum, while in return Britain will open up its markets to US beef and other agricultural products.

The Dow Jones finished up 0.6 percent at 41,368, as did the S&P 500, which closed at 5,663.

The Nasdaq climbed 1.1 percent to 17,928.

"It's a combination of the Fed not saying anything negative combined with the potential agreement between the US and the UK," said CFRA's Sam Stovall, referring to the Federal Reserve's relatively buoyant view of the US economy.

"And the implication that there could be additional agreements with other countries down the road," he said.

Among individual firms, shares in US aviation giant Boeing closed up 3.3 percent after US Commerce Secretary Howard Lutnick indicated the UK planned to announce a new order of jets worth some US$10 billion.

The enthusiasm in financial markets spread to cryptocurrencies, with bitcoin rallying on the news to trade above US$101,500 for the first time since early February. (AFP)