Hedge funds are getting slammed (again) after oil's shock surge followed a record shift in equities

• Hedge funds that specialize in bearish or short bets and quant funds may have gotten crushed after the price of crude oil spiked as much as 20% Monday, a fund manager in London told Business Insider.
• It's the second such shock for funds, after last week's record decline in "momentum" trades.
• One quant-fund source in London who got hit from last week's move said: "Seriously, what a year."
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Hedge funds that specialize in bearish or short bets and quant funds may have been crushed after the price of crude spiked as much as 20% Monday, a fund manager in London told Business Insider. The surge, triggered by attacks on Saudi Arabian oil facilities over the weekend, came as the hedge funds were already reeling from a sudden shift in equity markets.

As much as 5% of global oil supply was taken out of the market after the oil field attacks.

"Seriously, what a year," said a separate source at a hedge fund in London, who said this oil move, as well as an unheard of "momentum shift" last week that burned the fund, made for an "amazing" period in markets.

"It's the biggest demand shift for 100 years, and a lot of people were short or underweight," the London fund manager told Business Insider. "Many traders will have been rushing to close their position, and things might go higher if Trump and the US continue their bombastic mood on this."

In a rare move, an insider told Business Insider that BP allowed worried US clients to place orders from 5:00 p.m. central time Sunday in the US, so traders would be able to get their positions in place during the Asian market open.

Read More: Hedge funds are getting whacked in an 'unheard of' stock-market shift - and a leaked Morgan Stanley memo warns of possible pain for months

It's the second such shock for funds

A massive shift in the stock market from top-performing growth stocks to lower-performing names triggered a sharp shift in "momentum" last week, and has also crushed hedge funds.

"Everything that worked all year got sacked and whacked," a quant-hedge-fund source told Business Insider of the momentum move last week.

A Goldman Sachs note said the shift from growth stocks "ranks among the sharpest on record." Morgan Stanley sent a memo to clients last Wednesday, warning that the momentum trade might carry on causing pain for months.

The attack came at a bearish time for oil

For oil, the sudden jolt came at a time of bearish sentiment for the commodity. As the global economy continues to slow, oil demand was expected to decline in the coming months. Earlier this month, BP's finance chief indicated that global consumption would likely grow at around 1%, its lowest annual rise since 2014.

The move in oil upended those forecasts. Brent crude is currently trading up 10% at $66.34 as of 2.53 p.m. in London (9.53 a.m. in New York).

BP did not immediately respond to requests for comment.