Uncertainty descended Friday on Minnesota firms that do business in Europe, as they wrestled with the effects of Britain’s startling decision to exit the European Union.

The immediate consequences of Thursday’s vote were a plunge in global financial markets and a sharp rise in the U.S. dollar. What’s less clear is the long-term fallout, which will depend on the new relationship the British can negotiate with a likely adversarial European Commission and the potential for deeper political shifts as populist leaders in France and the Netherlands seized on the British decision and called for referendums in their own countries.

For corporate bosses in the Twin Cities with operations in Europe, the way forward may not be clear for months, or even years.

“You have to be wondering about your long-term investment strategy within the European Union,” said David Joy, chief market strategist for Ameriprise. “Maybe you put those plans on hold until you get a better sense of how this might sort itself out.”

Minnesota companies with operations in the United Kingdom disclosed little about their plans.

Cargill said it will “closely monitor the situation,” and Wells Fargo said it will “adjust our operating business model as needed.” Pentair, which is headquartered for tax purposes in Manchester, England, had no comment. 3M Co. and Ecolab also declined to comment.

London’s status as a global financial center could be undermined by the exit from the E.U., and banks that use London as their European trading headquarters will consider relocating to cities such as Dublin, Paris or Frankfurt.

Wells Fargo employs 875 people in London and has recently pushed to expand in the European Union.

“The U.K., and rest of the E.U., are very important markets for our customers and our international business,” said a statement from the firm, which has the largest bank operation in Minnesota. “We will adjust our operating business model as needed, to ensure we comply with any changing legal and regulatory requirements.”

Cargill employs 3,500 people at 22 locations in the U.K., including chocolate factories in Worksop and York, a massive chicken slaughtering facility in Hereford, and trading desks in London. The firm has been in the country since 1955.

“Cargill believed that there were distinct advantages for the U.K. and member countries to remain together as part of the European Union,” the Minnetonka-based food giant said in a statement Friday. “The priority now is to closely monitor the situation and ensure that our business interests are protected during the coming months, as the situation unfolds.”

Multinationals have probably already been doing contingency planning, but the problem is that no one knows how the situation will unfold, or how long it will take. The process of leaving the E.U. will take about two years, and renegotiating trade deals and regulatory agreements could take as long as a decade.

Leaders in Britain’s “leave” campaign have not said what their negotiating priorities will be, but to some extent the free flow of people, goods and services will be curtailed. The European Commission will not be inclined to agree to favorable terms with a renegade former member, for fear that might encourage other nations to leave the E.U., said Joy, of Ameriprise.

“These negotiations are going to be tough,” he said, “and I think rightly so.”

Big picture, however, the United Kingdom and Europe play a decreasingly important role in the global economy, and the panic in financial markets should subside soon, said Carol Schleif, deputy chief investment officer at Abbot Downing in Minneapolis.

“Most of the financial media still emanates from developed market money centers, even though fundamentals and demographics have shifted,” Schleif said. “This fans the flames of short-term hysteria, even though fundamentals don’t mesh.”

Schlief said the market was surprised by British voters’ decision, and the market does not like surprises or the likelihood of an emotional, messy, extended British divorce from the E.U.

But she does not expect a global economic downturn. Markets had rallied in recent days, with many investors believing Britain would decide to stay within the E.U., and those gains have been erased.

“Broadly speaking, currency changes, increases in fixed income and declines in stock prices are pushing various investments back to levels they were at approximately 10 days ago,” Schleif said.

The more troubling risk for global businesses is the potential for other countries to break off from the E.U. — highlighted Friday when leaders in France and the Netherlands called for “Frexit” and “Nexit” referendums.

“The bigger issue isn’t so much the U.K. leaving as it is the potential for this to cause other countries to rethink their position within the E.U., and that could be far more damaging,” said Erica Bergsland, director of research at Advantus Capital Management in St. Paul.

Most businesses, but medical device firms in particular, depend on uniform regulations in the European market.

“They really benefit from having a consistent regulatory framework,” Bergsland said. “If the E.U. breaks apart and companies have to deal with layers of regulation, that’s clearly a negative and makes it a lot more expensive.”