(ShareCast News) - Insurer Old Mutual is said to have received new approaches for its $900m controlling stake in its US asset management arm.The Financial Times cited four people briefed about the discussions as saying that the company has held preliminary talks with China's HNA Group, and US private equity firms TPG and Advent, but has failed so far to come up with a definitive agreement.Back in December, Old Mutual sold down part of its 66% stake in Old Mutual Asset Management to 51% on the open market as part of a process to break the company up into four parts following a strategic review. The company plans to separate into Old Mutual Emerging Markets, Old Mutual Wealth, Nedbank Group and OM Asset Management.Sources told the FT that China's HNA is still interested in a deal with Old Mutual as long as it can buy a majority stake in OMAM.Meanwhile, Boston and London-based Advent is also still interested in a transaction, and US firm TPG has given up on a deal.At 1150 GMT, Old Mutual shares were up 1.2% to 213.70p.