Japanese police investigators descend on the offices of AIJ Investment Advisors in Tokyo.
The firm's President, Kazuhiko Asakawa, is escorted from the building under arrest.
Japanese media reports say at least two other people have also been arrested.
Investigators are looking into AIJ's activities after it collected some 1.8 billion dollars during a nine year period, but posted losses of 1.32 billion.
AIJ was stripped of its registration as a discretionary asset manager last week when it was unable to account for most of its assets under management.
It's also accused of falsifying reports to investors.
More than 90 mostly smaller corporate pension funds invested money with AIJ.
Asakawa admitted in March that he'd covered up losses but said he'd been confident of recovering them and wasn't trying to cheat his clients.
Paul Chapman, Reuters