The inflows into stock ETFs and the outflows from stock mutual funds resulted in net outflows of $1.8 billion from stock funds overall during the weekly period, which marked the largest outflows in five weeks.

Nearly all of the investor withdrawals from stock mutual funds came from mutual funds that specialize in U.S. stocks, underscoring investors' fear that a pullback in Fed stimulus could derail the major rally in U.S. stocks this year.

Overall, ETFs and mutual funds that specialize in U.S. stocks had net outflows of $2.6 billion, also marking the biggest outflows from the funds in five weeks and resulting in the overall outflows from stock funds over the weekly period.

While investors soured on U.S. stocks, they still sought stocks of companies outside the U.S. Mutual funds and ETFs that hold stocks of companies outside the United States attracted about $830 million in net new cash.

Those inflows came even as fears of a Fed pullback disrupted global markets, resulting in the MSCI world equity index declining 0.2 percent for the week.

Investors pulled about $553 million out of emerging market stock funds in the week ended Wednesday. The funds have benefited from the Fed's bond-buying this year and lost fans in the latest week on fears of a Fed pullback, Tjornehoj said.

Taxable bond funds saw outflows of $689 million, marking their biggest outflows in eight weeks. Investors pulled cash out of taxable bond funds on worries that interest rates could spike higher if the Fed reduces its stimulus, said Tjornehoj.

The yield on the benchmark 10-year U.S. Treasury note rose to a three-month high of 2.87 percent on December 5 after strong U.S. jobs and economic growth data reinforced expectations that a Fed cutback was imminent.

Investors still sought funds that hold investment-grade corporate bonds, however, and committed $1.7 billion in new cash. That marked the biggest inflows into the funds in five weeks. Investment-grade bonds are viewed as safer because they sport higher-quality credit ratings.

Riskier high-yield junk bond funds attracted just $16 million in new cash, demonstrating investors' preference for safety but still marking and improvement from small outflows over the previous week.