NEW YORK, Jan 15 (Reuters) - Investors in U.S.-based mutual funds added $2.65 billion into bond funds at the start of the year after 14 straight weeks of outflows, data from the Investment Company Institute showed on Wednesday. Taxable bond funds particularly gained in the eight-day period ending Jan. 8, posting their first net advance since early October. But investors pulled money out of municipal bond funds, a 33rd straight week of net outflows, according to data from ICI, a U.S. mutual fund trade organization. Investors were also wary of funds that mainly hold U.S. stocks over the period, pulling out a net $3.36 billion. U.S. stocks kicked off the year with a whimper, with the Standard & Poor's 500 down 0.6 percent from the close of last year through the close of Jan. 8, in what some market participants worry could be a sign of a lackluster year to come. While stimulus from the U.S. Federal Reserve helped push U.S. stocks to a gain of nearly 30 percent last year, the Fed in December said it would start slowing its massive bond-buying program as the economy grows strong enough to stand on its own. Funds that specialize in stocks of companies outside the United States fared better in the most recent period, pulling in $2.72 billion. Hybrid funds, which can invest in stocks and fixed income securities, attracted $880 million in the latest period, down slightly from the previous week's inflows. The following table shows estimated ICI flows for the past five periods (all figures in millions of dollars): 12/11 12/18 12/23 12/31 1/8 Total Equity -1,203 171 2,466 6,198 -647 Domestic -4,525 -2,814 952 3,499 -3,362 World 3,322 2,985 1,514 2,699 2,716 Hybrid 864 441 827 1,082 880 Total Bond -6,874 -8,090 -3,464 -2,812 2,647 Taxable -4,299 -5,568 -2,064 -440 2,994 Municipal -2,575 -2,522 -1,400 -2,372 -347 Total -7,213 -7,477 -172 4,467 2,881 * Hybrid funds can invest in stocks and/or fixed-income securities.