Short sellers were sitting on more than $7 billion in profit from the mass sell-off of bank shares by the end of March, their largest windfall since the global financial crisis in 2008, according to data firm Ortex.

The collapse of Silicon Valley Bank and the emergency rescue of Credit Suisse by domestic rival UBS headlined a chaotic month for the global banking sector.

Fears of contagion sent shares tumbling across the U.S. and Europe, and the losses were compounded by further monetary policy tightening from the U.S. Federal Reserve.

Short selling is the practice of borrowing an asset and selling it on in the hope of buying it back at a lower price, pocketing the difference and profiting from the decline of its value.

Hedge funds shorting bank stocks were sitting on a total of $7.25 billion in unrealized gains over the course of the month, according to Ortex.

“ORTEX data shows that March was the single most profitable month for short sellers in the banking sector since the 2008 financial crash,” company co-founder Peter Hillerberg said Thursday.

Those with short bets against the failed SVB topped the pile with unrealized profits totaling more than $1.32 billion, according to the data. Fellow California-based bank First Republic netted short sellers almost $848 million as its shares sank 89% over the course of the month.

Credit Suisse’s capitulation made those with short positions against the bank’s Swiss-listed stock around $610 million in unrealized profit in March, Ortex data showed, with a combined $683.6 million generated from shorts on both its Swiss- and U.S.-listed shares.

The banking crisis ripple effect also seized Deutsche Bank stock despite the absence of any discernible catalyst, which prompted German Chancellor Olaf Scholz to publicly declare that the lender is a “very profitable bank” and that there was “no reason to be concerned.”

Deutsche stock yielded an unrealized $39.9 million for short sellers in March.

“The shares on loan in DBK went up by 496% during March, much of this at the end of the month when the price of the stock went up, which caused some of the profits for short sellers to be lost,” Ortex said, adding that it estimates that just over 5% of the bank’s free-float shares are currently shorted.