SAN FRANCISCO/NEW YORK (Reuters) - U.S. companies, facing investors in their first profit reporting season since Great Britain voted to leave the European Union, are broadly conceding that the so-called “Brexit” could weigh on earnings.

Traders work on the floor of the New York Stock Exchange (NYSE) in New York City, U.S., July 18, 2016. REUTERS/Brendan McDermid

Companies from General Motors GM.N to Yum Brands YUM.N to FedEx FDX.N say they do expect a hit, though it is too soon to tell how deep it may be or when it will come.

Wall Street investors were originally rattled by the Brexit vote and independent analysts have suggested it could cost U.S. companies billions of dollars in earnings due both to currency factors and also to lost sales in Europe. At least 49 of 85 S&P 500 companies with quarterly conference calls since the end of June have talked about Brexit.

On Thursday, GM said it was considering cost cuts in Europe to offset up to $400 million of potential headwinds triggered by Brexit.

“The result of the vote has adversely impacted the British pound and the uncertainty has put a strain on the UK automotive industry,” Chuck Stevens, executive vice president and chief financial officer told investors.

Visa Inc V.N, which completed its acquisition of Visa Europe last month, late Thursday said Brexit will affect currency exchange rates and economic growth in the short term, and that the vote has "introduced significant uncertainty."

PayPal Holdings PYPL.O said Brexit will have some effect on its regulatory environment, while General Electric GE.N on Friday said Brexit adds "another point of volatility."

FedEx Corp, in its annual report filed July 17, said Britain’s exit could result in a global economic downturn, which could depress the demand for its services as well as create new trade regulations.

S&P 500 corporations overall depend on Europe for 8 percent of their revenue, with just 1.9 percent of revenue flowing from Britain, according to S&P Dow Jones Indices.

Companies that don’t see Brexit hurting their results now may change their tune as Britain’s separation from the world’s largest trade bloc unfolds over years, with Britain not expected to even begin the exit process before the end of 2016.

Ahead of the June 23 vote, economists had widely warned that leaving the EU could create global financial instability and an economic slump in Europe.

The vote resulted in an immediate selloff of global and U.S. stocks and a rise in the U.S. dollar against major currencies - a move that, if sustained, could hurt U.S. exporters. Many now emphasize that the negative economic effects of Brexit will occur over years instead of months.

“My guess is that companies are sensing the same thing, and don’t know how to quantify it yet,” said Steve Chiavarone, portfolio manager at Federated Investors.

CURRENCY IMPACT SEEN

Brexit could cost North American and European companies some $35 billion to $40 billion over coming quarters in currency impacts alone, according to a report released this week by FiREapps.

Even companies that expect a Brexit effect still could do well. Yum Brands YUM.N, for example, said it expected Brexit-related currency charges to hit its bottom line by about $50 million over the rest of the year. But shares of Yum, which operates restaurants including Taco Bell, still surged on signs its China business was strengthening.

GM, while announcing its potential cost cuts, said it was raising its overall outlook for the rest of the year.

Many other companies are also shrugging off the Brexit question. IBM IBM.N said this week that it expects no effect from Brexit on its results for this year, while Halliburton HAL.N said it doesn't see Brexit having a dramatic effect.

A U.S. dollar index .DXY is up 4.2 percent since the June 23 vote after easing earlier in the year, though it remains down 1.2 percent since Dec. 31.

For most companies, there is still a lot of wait-and-see involved in their Brexit plans.

"Like everybody else on the planet, we're waiting to see if there's really going to be an impact or not," said Tom Lynch, chairman and chief executive of sensor maker TE Connectivity TEL.N.

(This version of the story has been refiled to correct spelling of firm to Federated Investors, not Federal Investors in paragraph 13)