(Bloomberg) -- Pacific Investment Management Co.’s biggest mutual fund had the worst year of client withdrawals in the history of fund management as the firm lost both of its co-chief investment officers, Bill Gross and Mohamed El-Erian.

Investors pulled $19.4 billion from Pimco Total Return Fund in December, bringing redemptions in 2014 to a record $105 billion, according to data compiled by Bloomberg using information from Newport Beach, Calif.-based Pimco and Morningstar Inc. Assets in the world’s biggest bond fund fell to $143.4 billion as of Dec. 31, according to a statement from Pimco, down by more than half from a peak of $293 billion in April 2013.

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