Investors pulled $7.3 billion out of Pacific Investment Management Co.'s mutual funds in March, the 10th straight monthly net redemption.

The outflow from Pimco's U.S.-based funds grew from $2.5 billion in February and $5.7 billion in January, according to data from fund tracker Morningstar Inc.

The latest setback underscores the challenges confronting the Newport Beach, Calif.-based money manager following a year of record redemptions and a management shake-up.

Both stock and bond funds suffered in March. Pimco's bond funds posted $5.6 billion in outflows, while stock funds had $466.2 million in redemptions.

Pimco has suffered $15.4 billion in outflows in the first three months of the year, following a $30 billion withdrawal in 2013, according to Morningstar.

The Pimco Total Return Fund, the firm's flagship bond fund, suffered $3.1 billion in outflows last month. The fund saw its assets decline to $232 billion at the end of March, down from $236.5 billion in February. It remains the world's largest bond fund by assets.

One of Pimco's competitors, the fund family DoubleLine, posted 2014 inflows of $84.9 million through March this year, although the company saw outflows of $13.7 million in March, according to Morningstar.

"Investor's confidence is fading," said Adrian Miller, a global market strategist at GMP Securities LLC. He said that Pimco's image has been "somewhat damaged" by the events surrounding the surprising departure of the firm's chief executive Mohamed El-Erian.

A Pimco spokesman did not immediately return a request for comment.

Write to Min Zeng at min.zeng@wsj.com and Kirsten Grind at kirsten.grind@wsj.com

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