Boaz Weinstein, founder and chief investment officer at Saba Capital Management, speaks during the SALT conference in Las Vegas, Nevada, U.S. May 17, 2017. REUTERS/Richard Brian

LONDON (Reuters) - New York-based Saba Capital Management, famed for its winning bet against the JPMorgan Chase JPM.N trader known as the 'London Whale', is closing its office in London's Mayfair district, two sources close to the situation told Reuters.

The $1.8 billion (£1.4 billion) hedge fund firm will move European trading operations to New York, said one of the sources with direct knowledge of the matter, becoming the second U.S. fund firm to do so this year after Goldman Sachs Investment Partners.

The reason for Saba Capital’s move was not clear although it comes at a time of uncertainty for fund firms based in Britain as talks begin on the country’s exit from the European Union.

It is also not clear whether the three individuals at the London office currently registered with the British regulator will relocate to the U.S. office or find new jobs.

Saba founder Boaz Weinstein made his name from the bet against JPMorgan, linked to corporate default rates. That helped assets at the firm - housed in New York’s art deco Chrysler Building - peak in 2012 at $6 billion.

A subsequent period of underperformance saw a number of investors pull their money, only for Saba to bounce back and attract fresh capital with a market-beating 3 percent gain in 2015 and returns of 22 percent in 2016, one of the sources said.

The source also said the firm’s performance was flat in the in the first four months of this year. It has had an office in London since early 2012, according to the filings from Britain’s Financial Conduct Authority.

Weinstein, a former Deutsche Bank trader, started Saba in 2009.