Gross, 70, had been clashing with the firm's executive committee and had threatened to resign multiple times, a source familiar with the situation said. The committee had planned to accept his latest resignation from the post of chief investment officer on Saturday.
The surprise development, which rattled the U.S. bond market, came the day before Pimco and its parent, German insurer Allianz SE, planned to dismiss Gross, the source said.
Gross will manage the Janus Global Unconstrained Bond Fund beginning on Monday, Janus said in a statement. The fund, started in May, has just $13 million in assets.
Dan Ivascyn, one of Pimco's deputy chief investment officers, is expected to replace Gross, who according to Forbes has a net wealth of $2.3 billion, a source familiar with the matter said.
"Pimco and Bill Gross are synonymous," said Todd Rosenbluth, director of mutual fund research at S&P Capital IQ. "It will be extremely hard to think of Pimco and Bill Gross as separate, and it will take time for investors to realize that he no longer is going to play a role at one of the world’s largest fixed income managers."
PERIOD OF UPHEAVAL
The departure is the latest twist in a tumultuous year for Gross, long dubbed "the bond king" for his prowess in fixed-income investing, and for the firm he helped build into a $2 trillion powerhouse since co-founding it in 1971.
Earlier this year, his co-chief investment officer, Mohamed El-Erian, left Pimco, causing a highly public falling out between the two long-time colleagues. El-Erian remains at Allianz.
Gross' flagship Pimco Total Return Fund, the world's largest bond fund, with more than $220 billion in assets, has suffered nearly $70 billion of investor withdrawals over the past 16 months, while its performance has lagged its peers and the wider bond market.
His departure could lead investors to pull hundreds of billions of dollars in assets from Pimco and invest it with Janus, a Morningstar analyst said.
Pimco had prepared investors for the possibility of succession as recently as two weeks ago, said Karissa McDonough, a fixed income strategist at People’s United Wealth Management.
“They were trying to reassure us by driving home the point that they’re not so dependent on Bill Gross anymore,” McDonough said.
The departure also comes within days of news that the U.S. Securities and Exchange Commission was investigating whether a popular Pimco exchange-traded fund that Gross ran and that was launched to mimic the strategy of the much larger Pimco Total Return Fund, had artificially inflated returns.
The probe is not related to Gross' resignation, a spokeswoman for Allianz said.
Shares of Allianz fell more than 8 percent in German trading.
The news also sent yields of U.S. Treasury bonds higher and prices lower. Analysts said traders sold Treasuries on bets investors would pull cash from Pimco.
The impact was also felt in the niche market of inflation linked bonds known as Treasury Inflation Protected Securities (TIPS), where breakevens - the difference in yield between TIPS and a comparable maturity treasury - were narrower across the curve, denoting an underperformance of TIPS.
According to the latest public data, PIMCO owned $79.8 bln of TIPS and was the largest holder in 25 of the 38 outstanding issues, according to Thomson Reuters publication IFR.
JANUS' TRIUMPH
Gross' move was seen as a huge coup for Janus, which has less than $180 billion in assets under management, less than the Total Return Fund and a fraction of Pimco's total assets.
Janus shares were up nearly 38 percent, or $4.19, at $15.30 in late afternoon trading on the New York Stock Exchange.
"I look forward to returning my full focus to the fixed income markets and investing, giving up many of the complexities that go with managing a large, complicated organization," Gross said in a statement.
Gross said he had chosen Janus because of his longstanding relationship with Chief Executive Richard Weil, who spent 15 years at Pimco before taking his current job in 2010.
Gross had also considered joining DoubleLine Capital. The investment firm's head, Jeffrey Gundlach, said he had met with Gross last week to discuss a possible role there.
Gross will be based in a new Janus office to be set up in Newport Beach, California, where Pimco is based.
(Reporting by Dan Burns, Paritosh Bansal, Jennifer Ablan, Luciana Lopez, Jonathan Gould, David Randall and Sam Forgione; Writing by Dan Burns and Megan Davies; Editing by Lisa Von Ahn and Steve Orlofsky)
By Paritosh Bansal and Jennifer Ablan
