FILE PHOTO: A view of the Goldman Sachs stall on the floor of the New York Stock Exchange in New York, U.S., July 16, 2013. REUTERS/Brendan McDermid/File Photo

(Reuters) - Goldman Sachs Group Inc GS.N is building a 1.1 million square foot office in London with initial occupancy slated for 2019, it said in a regulatory filing on Monday, even as global banks grapple with risks around Brexit.

When completed, the new London building would be about half the size of Goldman’s executive offices in downtown New York at 200 West Street.

The bank currently has around 1.2 million square feet of office space in London in various properties, including its current European headquarters at Peterborough Court.

Goldman also has flexibility to adjust the number of floors it takes in the new building, according to a source familiar with the situation, so it is not committed to occupying the entire office. That option was put in place prior to the Brexit vote.

Goldman is continuing to expand in London even as global banks have begun signaling how they will put plans into action to cope with a “hard” exit by Britain from the European Union.

Since the Brexit vote, U.S. banks have talked with governments and regulators in several major European cities like Dublin, Frankfurt and Paris to look at where to base certain operations.

Goldman said on Monday that Brexit could “materially adversely affect” how it operates businesses in Europe and could require it to restructure some of its operations.

The bank was considering moving some assets and operations to Frankfurt, sources told Reuters in October.