But in recent months the exodus from the firm's flagship Pimco Total Return Fund has slowed from $11.6 billion in January to just $2.7 billion in May and $3 billion in net outflows in June. Figures for July due out later on Tuesday are expected to show a further decline of about $3 billion, according to a source familiar with the situation.
Its strong relative performance has helped to start to turn the tide.
The fund, which lost its crown as the world's largest bond fund in April to the $144.2 billion Vanguard Total Bond Market Index fund, is returning 1.56 percent so far this year, surpassing 96 percent of other funds in its intermediate-term peer category.
And Alina Lamy, senior analyst of markets research at Morningstar, said that the $47.4 billion Pimco Income Fund, which Ivascyn personally oversees, is also outperforming 96 percent of its peers in the multisector-bond category. The fund has attracted $8.7 billion since Gross' departure, though that is tiny against the $119.4 billion that has left Pimco Total Return in that time, according to Lamy.
Some major clients are no longer considering redeeming money—or in bond market parlance they have removed Pimco from their "watchlists."
The $45.9 billion Teachers' Retirement System of the State of Illinois, with $2.4 billion invested through the firm, removed Pimco from its list in May, and the $2.4 billion Sonoma County Employees' Retirement Association did the same in June.
To be sure, the recovery at Pimco still has some way to go.
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Big bond rivals BlackRock Inc, Vanguard Group, DoubleLine Capital and TCW Group have been beneficiaries - not only because of the departures of Gross and El-Erian, but also because of Pimco's weak performance in 2013 and 2014. Gross was there for most of that time and El-Erian for more than half of it.
The rivals are still taking potshots at Pimco.
"It is too early to make a judgment on Pimco," said Jeffrey Gundlach, the co-founder of DoubleLine, which oversees $76 billion in assets. "Less than one year is too early for any investment strategy. But I do think it would behoove them to clarify their investment process absent Bill Gross," he said referring to a sense that the firm is no longer transparent about the way it operates.
Gundlach's DoubleLine posted its 17th consecutive month of cash inflows in June and the Los Angeles-based firm has hired six Pimco employees since April 2014.