Old Mutual has set a deadline of two weeks for tentative bids for OMGI.
The company has is aiming for at least £500m from the sale, which is being run by Goldman Sachs, Reuters reports.
Old Mutual has reportedly approached the US firm that invested in Gartmore to facilitate a buyout of the single strategy division of the asset manager, led by OMGI chief executive and star fund manager Richard Buxton.
Hellman & Friedman is among the private equity houses that have been sounded out by Old Mutual, alongside Cinven and CVC Capital Partners.
They have until 29 September to make their bids.
OMGI, the single strategy part of the business, is being separated from the multi-asset arm before the group’s “managed separation” next year.
The multi-asset arm will run by investment director Paul Simpson, and Old Mutual says it has no plans to reshuffle managers or product ranges.