By Maiya Keidan and Lawrence White

LONDON (Reuters) - Pacific Investment Management Co (Pimco) has poached Emmanuel 'Manny' Roman from Man Group <EMG.L>, the world's biggest listed hedge fund, as it tries to reverse a slump in fortunes since co-founder Bill Gross left the fund manager in 2014.

Pimco built its reputation largely through its management of fixed income securities, but has been under pressure to reverse a drop in assets under management since the abrupt departure of Gross, nicknamed 'the Bond King'.

California-based Pimco, owned by German insurer Allianz <ALVG.DE>, managed $1.5 trillion as of the end of March, down from peaks of $2 trillion in the first three months of 2013.

The asset manager has tried to diversify its investor base in recent years to attract clients buying equity products but has struggled to replicate its success in fixed income investment.

Roman, 52, will take over as Pimco chief executive officer on Nov. 1, replacing the incumbent Douglas Hodge who will stay on as senior advisor.

"Manny's deep understanding of global markets, unique skills in investment management and appreciation of Pimco's macro-based investment process make him the ideal executive to position the firm for long-term success," Managing Director and Group Chief Investment Officer Daniel Ivascyn said in a statement.

The Newport Beach-based firm has parted with several top executives it hired to help compete more strongly in other asset classes, including Virginie Maisonneuve, and Neel Kashkari, who is now Minneapolis Federal Reserve President.

A Pimco memo seen by Reuters last month showed that the company, which employs about 2,300 people, was planning to cut some 3 percent of its workforce as it grappled with falling assets and the closure of some unpopular funds.

Gross's departure followed a phase of weak returns, which prompted criticism of his management style. He later claimed executives plotted to eject him from the firm and divide the spoils of his bonus among themselves in a lawsuit launched in October 2015.

He is asking for at least $200 million in compensation from Pimco although he has said proceeds will be donated to charity. Pimco is contesting the claim and has argued it had "good cause" to oust Gross.

ELLIS TAKES CHARGE

Roman, a wine collector who donated 15,000 pounds ($19,650) to the defeated 'In' campaign in Britain's referendum last month on EU membership, has led Man since 2013 and through a period of turmoil for the hedge fund firm..

The fan of English Premier League team Arsenal joined Man Group after it merged with GLG, where he was co-chief executive officer and "the real power of the group", according to Reuters sources.

Prior to joining GLG in 2005, Roman worked at U.S. investment bank Goldman Sachs for more than 18 years. He is also a board member of France's second listed biggest bank Societe Generale <SOGN.PA>.

Under Roman's leadership, Man restructured to try to reduce its dependence on its trend-chasing computer-driven business AHL, though Citi said on Wednesday the firm continued to be "heavily reliant" on AHL fund performance and flows.

Man lost $100 million in assets in the funds it manages in the first quarter of 2016, trimming them to $78.6 billion, though AHL helped prop up its fund manager-led equities business, GLG.

Roman's current annual salary at Man was $1.1 million and he received a cash bonus for 2015 of $2.5 million.

Luke Ellis will succeed Roman as CEO of Man Group on Sept.1, the company said. Jonathan Sorrell will continue as president of the firm as well as chief financial officer.

Ellis currently works alongside Roman as president, is a member of the executive committee and oversees Man's four investment units. He is likely to take a similar approach to Roman, according to analysts at Bank of America Merrill Lynch.

"Roman has done a good job in steering Man toward its current, robust state," said the report. "Ellis ... could be seen as a continuity candidate."

Man's shares opened 3 percent lower at 119 pence but had recovered some ground to trade 0.9 percent lower at 121.2 pence by 1315 GMT.

(Writing by Sinead Cruise; Editing by David Clarke/Keith Weir)