Investors fled U.S. equity funds at the fastest pace on record in the week ended Wednesday, according to data from Lipper.

More than $46 billion was redeemed from U.S. stock mutual funds and ETFs between Dec. 5 and 12, the largest weekly outflow since Lipper began tracking weekly flows in 1992. The data comes amid a continued stock market selloff that’s driven the S&P 500 SPX, +0.35% into correction territory and left it on track for its biggest quarterly loss since the third quarter of 2011.

The figure is also nearly twice as large as any other week on record, underscoring the increasingly cautious stance being taken by investors in the final quarter of 2018.

According to Tom Roseen, head of research services at Lipper, investor caution has been the result of a growing number of macro headwinds, from uncertainty surrounding trade talks, to Brexit and Italian budget negotiations, and growing volatility in U.S. equity markets.

“This record outflow is alarming and unusual,” Roseen told MarketWatch, arguing that it may be evidence of a “final capitulation” on behalf of equity investors.

At the same time, there are transitory factors he pointed to that may result in money flowing back into equities before long. One is that several major funds went “ex-dividend” on Dec. 12, meaning they paid out capital gains and income distributions for the year, and much of that money will be immediately reinvested. Other transitory factors could be tax related, as investors close out losing positions to reduce their capital-gains taxes for the year.

The big winner from all this selling were money-market funds, which saw $81.2 billion in inflows, according to Lipper.

The demand for money market instruments, or fixed-income securities with a maturity of a year or less, have surged to the point that their chief buyers like corporate treasurers are complaining of the difficulties of sourcing such paper from broker-dealers.

“Before you’d have a block of bonds in a dealer’s inventory for more than an entire day. Now, you may see it go out in 5 or 10 minutes,” said Eric Souza, senior portfolio manager at SVB Asset Management, who helps manage and invest the cash stockpiles of tech firms.

A separate analysis of flow data by Bank of America Merrill Lynch estimated outflows from U.S. equity funds at $27.6 billion in the week ended Wednesday, which is the second largest outflow on record, with the largest coming the week ended Feb. 7.

The BofA analysis is based on data from EPFR global, and the discrepancy between the two is due to Lipper aggregating data from funds that report flows both weekly and monthly to calculate a moving average, whereas EPFR only includes funds that report weekly.