Goldman Sachs Chief Executive Lloyd Blankfein has regularly used the firm’s under-construction London HQ as a stick to beat the U.K. government with during the Brexit process.

A vociferous opponent of Brexit, Blankfein has regularly tweeted about the possibility of the firm moving some of its staff from London to Frankfurt, leaving some of the 850K SF building empty.

Now the company is looking to cash in on the building, in what could prove to be one of the savviest real estate plays in London in recent years.

The building is now officially on the market for £1.3B, according to a report in Estates Gazette. Bloomberg reported earlier this year that Goldman Sachs was mulling the sale of the HQ. CBRE and Eastdil Secured are advising on the sale.

Goldman will take a 25-year lease at a rent of about £70/SF, meaning a price of £1.3B will represent a yield of about 4%, EG said.

The Midtown building can accommodate about 9,600 staff. It is scheduled to open next year.

A sale at £1.3B could see Goldman double its money on the HQ, according to Bisnow research. It paid around £150M to buy the buildings that now make up the development site, and the construction and fit-out contract totalled £500M.