Technology giant Apple is "very optimistic" about the UK's future post-Brexit, its boss has told the prime minister.
Apple's chief executive Tim Cook met Theresa May at Downing Street and said he thought the UK would be "just fine"' outside the European Union.
The company plans to build a new UK headquarters in London.
His comments came as the US Chamber of Commerce said US firms had been delaying UK investment decisions.
It has thousands of members in the US, including many large multinationals.
Its head of international affairs, Myron Brilliant, told the BBC
firms were worried about future trade rules.
He said they thought there could be new regulatory challenges once the UK was no longer in the EU.
'Bumps in road'
However, at his meeting with the prime minister, Mr Cook said:"We're a big believer in the UK - we think you'll be just fine.
"Yes there will be bumps in the road along the way but the UK's going to be fine."
In a statement following the meeting, Apple said: "We are proud that Apple's innovation and growth now supports nearly 300,000 jobs across the UK. "
Apple's new UK headquarters will be in the redeveloped Battersea Power Station. Last year the company said it would move 1,600 staff there in 2021.
Mr Cook described it as a huge headquarters and said the company was "leaving significant space there to expand."
Earlier the US Chamber of Commerce's Mr Brilliant told BBC Radio 5 live's Wake Up To Money: "They're [US firms] worried about what the transition rules are going to look like.
"They're worried about whether there are going to be new regulatory challenges, impediments, and so we're going to see how that plays out over the next two years.
"One also expects that the UK-EU will have a trade agreement. But what we're saying from Washington is that we're going to be vested stakeholders, as we have been in terms of our businesses here."
He added: "Of course, some companies are holding back investment to see how this plays out. That makes sense.
"But there is no question that Europe is an important part of any company's international strategy.
"And so it's not that they're going to pull back from Europe, but they are going to realign their investments, depending on how these negotiations go."