MADRID (Reuters) - Britain’s exit from the European Union will likely trigger a period of high uncertainty that may significantly impact Banco Santander’s business, the Spanish lender said in a filing to the U.S. Securities and Exchange Commission.

FILE PHOTO: A Santander logo is seen in Rio de Janeiro, Brazil, September 6, 2017. REUTERS/Sergio Moraes - RC13E44F74D0/File Photo

The document, which details Brexit’s potential impact on Santander’s UK operations including its operating results and its ability to hire and retain staff, was the most specific statement to date from the euro zone’s largest bank by market value.

“There remains significant uncertainty as to the respective legal and regulatory environments in which we and our subsidiaries will operate when the UK is no longer a member of the EU,” the bank said in a filing on Friday to the SEC.

“This uncertainty, and any actions taken as a result of this uncertainty, as well as new or amended rules, may have a significant impact on our operating results, financial condition and prospects,” it said as part of risk assessment.

In Britain, Santander’s net profit fell 8.8 percent year-on-year in the second quarter, partly due to ongoing competitive pressure on income and costs related to regulation and digital projects.

Banco Santander also said in its filing it was finalizing the implementation of restructuring and strategic initiatives, such as the ring-fencing of retail banking activities in the UK, its third-largest market.

The bank has already transferred 22.9 billion pounds ($29.9 billion) of assets and 20.7 billion pounds of liabilities to its Madrid-based parent group in a move to comply with new rules that come into force next year.

Banks operating in Britain must separate deposit-taking operations from riskier investment banking activities before January 2019. Personal and small business banking services will have to be provided by a ‘ring-fenced bank’.

Britain’s looming exit from the EU and political uncertainty in Brazil are expected to test the management skills of Santander’s new chief executive Andrea Orcel [nL8N1WC37J].

So far this year, Santander has lost around 20 percent of its value as lenders face pressure from low interest rates, especially in Spain, its second-biggest market, while trying to shift from traditional commercial banking towards more digital-oriented lending to compete with fintech startups.