Investors in U.S.-based funds poured $4.6 billion into taxable bond funds in the latest week while limiting their commitments to stock funds, taking profits after stellar stock market gains in 2013, data from Thomson Reuters' Lipper service showed on Thursday.

Bond fund inflows for the week ended Jan. 8 were the biggest since last May. Stock funds, meanwhile, attracted $1.9 billion, their smallest inflows in three weeks, highlighting investors' reduced appetite for equities after last year's record-breaking rally.

"Investors are skeptical that the momentum in the U.S. stock market we had in 2013 will flow into the new year," Jeff Tjornehoj, head of Americas research at Lipper, said of the preference for bonds.

Funds that hold investment-grade corporate bonds, which are viewed as safer than high-yield bonds given higher-quality credit ratings, attracted $3.1 billion in new cash, also the biggest inflows into the funds since last May.

Investors may have poured cash into investment-grade bond funds in an attempt to gain exposure while valuations are relatively cheap, Tjornehoj said. The Barclays U.S. Corporate Investment Grade bond index fell 1.5 percent last year, posting its worst performance since 2008.

Federal Reserve Chairman Ben Bernanke triggered a bond market selloff and outflows from bond funds last year when he told Congress on May 22 that the central bank could begin scaling back its monthly bond-buying stimulus later in the year if the U.S. economy looked strong enough.

Among investment-grade bond funds, funds that hold bank loans attracted over $903 million, marking their strongest turnout since September. The funds, which are protected from rising interest rates by their peg to floating-rate benchmarks, attracted sizable inflows of about $62.8 billion in new cash last year on fears of rising interest rates.

Investors were also willing to take greater risk in bonds, committing $146 million to funds that hold emerging market debt, marking the first net inflows to the funds since August.

Funds that hold high-yield junk bonds attracted $642 million, reversing the prior week's outflows.

Investors showed a preference for stocks of companies outside the United States in the latest week, even as MSCI's world stock index fell 0.8 percent over the period. Funds that hold non-U.S. stocks attracted $2.5 billion in new cash, marking their biggest inflows in six weeks. Emerging market stock funds took in $337 million in their first inflows in five weeks.

Funds that mainly hold U.S. stocks had outflows of $613 million, marking their first withdrawals in three weeks. The Standard & Poor's 500 stock index fell 0.5 percent over the weekly period.

Investors were cautious, with some taking profits after the index rallied 29.6 percent in 2013. Retail investors accounted for the inflows into stock funds in the latest week. Stock mutual funds attracted all of the $1.9 billion in net new cash into stock funds, while stock exchange-traded funds had meager outflows of $2.5 million. ETFs are generally believed to represent the investment behavior of institutional investors, while mutual funds are thought to represent the retail investor. Institutional investors soured on money market funds in the latest week, resulting in $6.8 billion in net outflows from the funds, the first outflows in three weeks.

The funds, which are low-risk vehicles that invest in short-term securities, are viewed as a safe place to park cash.

The weekly Lipper fund flow data are compiled from reports issued by U.S.-domiciled mutual funds and exchange-traded funds.