(Bloomberg) -- Two years of client withdrawals at Pimco's flagship have cost it the title of the world’s biggest bond mutual fund.

Investors pulled $5.6 billion from the Pimco Total Return Fund in April, after redemptions of $7.3 billion in March and $8.6 billion in February, according to estimates from the Newport Beach, Calif.-based firm. With assets of $110.4 billion, the fund fell behind the index-tracking Vanguard Total Bond Market Index Fund, which had $117.3 billion as of April 30, according to preliminary data.

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