John Burbank's Passport Capital, which famously shorted the subprime mortgage crisis, is rapidly shrinking

John Burbank's Passport Capital is shrinking.

The firm is managing just $900 million, about half of what it did at the start of the year.

In an investor letter dated July 31, the firm told clients:

"For the second quarter, the Fund had net outflows of $480 million. Firm-wide, net outflows (not including the Long Short hedge fund strategy liquidation, effective 4/30/2017) totaled approximately $565 million. At quarter-end, net of June 30th redemptions, Fund assets stood at $275 million and Firm assets totaled approximately $900 million."

Earlier this year, Passport shuttered its long-short fund, which managed about $833 million.

Passport, in hedge fund assets, managed about $2.1 billion firmwide at the start of the year, according to the HFI Billion Dollar Club ranking.

The firm had already been bleeding assets, as that start-of-the-year figure was 45% lower than at the start of 2015, per HFI. A spokesperson did not immediately return calls seeking comment in time for publication.

Burbank famously shorted the subprime mortgage crisis. Investors in Passport's flagship fund, the Passport Global Strategy, got a 219% payout in 2007, according to a Forbes report from the time.

The Passport Global fund is down 16.% net for the one year trailing to end of July 2017.