Aviva Investors and Standard Life Investments (SLI), the two biggest shareholders in F&C, have clashed on Bank of Montreal's (BOM) proposed £708 million takeover of the firm.
In the wake of the deal, analysts at Canaccord Genuity have also suggested the length of the time needed for regulatory approval could open F&C up to rival bids.
Earlier in the day Bank of Montreal and F&C agreed terms on an all-cash £708 million takeover. The deal, which offers shareholders 120p per share alongside a 2p dividend, provides a hefty 30% premium to the 93.5p share price at close on 24 January.
However Standard Life Investments, which owns a 10.2% stake in F&C, believes the asset manager can be sold for a better price.
'We note that F&C have recommended a cash offer from the Bank of Montreal. The price agreed represents an attractive valuation from the standpoint of the Canadian Bank. Consequently we intend to keep our options open should another suitor for F&C emerge,' SLI global head of equities David Cumming said in a statement.
This contrasts with F&C's largest investor Aviva, which owns 12.1% of the firm and has already pledged to vote in favour of the deal.
'Given board and management backing for the BOM offer and a valuation that is within our range of possibilities (albeit at the bottom end), we are comfortable providing our support to the transaction,' Aviva Investors head of UK equities David Lis told Wealth Manager.
Analysts believe the delay in the deal getting the green light could set up a bid battle for F&C.
'Regulatory approval will lengthen the time of the acquisition with approvals needed from regulatory bodies in Portugal, Luxembourg, Netherlands, Canada, UK and Hong Kong,' Canaccord Genuity analyst Arun Melmane said.
'The all cash share offer remains in the ball park of intrinsic value of F&C, in our view the length of the time needed for regulatory approval could bring other potential bidders into the arena.'
According to Reuters, three retail funds accounted for part of the SLI stake towards the end of last year. Karen's Robertson's UK Equity Income and UK Equity Growth funds held 0.68% and 0.23% at 31 October and 30 September respectively, while the firm's Ethical fund owned a 0.13% interest in September.
Other top investors in F&C included Sanjeev Shah, who owned 4.48% via his Fidelity Special Situations fund at the end of December before he handed the fund to Alex Wright. Meanwhile the team of Leigh Harrison and Richard Colwell controlled 1.46% through their Threadneedle UK Equity Alpha Income fund on 31 October.