NEW YORK (Reuters) - Mutual fund investors punished U.S.-based stock funds with their seventh consecutive week of withdrawals and their largest outflows so far this year, Investment Company Institute (ICI) data showed on Wednesday.

A flag flutters in the wind outside the New York Stock Exchange November 5, 2012. REUTERS/Chip East

Stock funds based in the United States returned $7.9 billion in cash to investors, adding to a near-two-month streak that has swept nearly $32 billion from the funds. That is the largest weekly withdrawal for those funds since investors pulled $8.3 billion in December, according to ICI data through the week ended April 27.

The funds' poor result comes despite a rebound in U.S. stock prices. The benchmark S&P 500 .SPXTR is up 13 percent from its February low. Yet fund investors have been less impressed with economic growth prospects following meek first-quarter corporate earnings.

“Though first-quarter earnings season has been moderately better than expected,” projections for the year are flat, said Todd Rosenbluth, director of ETF & mutual fund research for S&P Global Market Intelligence. “This is a drag of demand for U.S. equity strategies.”

Investors pulled $5.5 billion from U.S.-based funds focused on domestic companies and another $2.4 billion from international stock funds, the data showed.

Including exchange-traded funds, the outflows to U.S.-based equity funds were a more moderate $3 billion, ICI said.

“Investors have been rotating toward equity ETFs and away from equity mutual funds for a longer period of time, as investors favor a lower cost alternative,” said Rosenbluth.

Investment-grade bond funds attracted $3.1 billion, their ninth week in a row drawing new money. Riskier high-yield funds added $924 million. Overall, bond funds absorbed $8.3 billion in new cash, according to ICI, a fund trade group.

“The Federal Reserve’s citing of disappointing economic data in its recent decision to hold off raising fed funds rate, investors have been focusing on the safety of investment-grade bond funds,” Rosenbluth said.

Meanwhile, U.S. municipal bond funds took in $1.9 billion and taxable government bond funds gathered $559 million, ICI said, extending a streak of popularity for the relatively safe funds that has lasted the entire year.