Two rival parties are preparing bids for NFU Mutual, to force the company to list on the stock market.
John Murray, a former director of the insurer, is in talks with a major financial institution to fund a buyout for the company.
A rival consortium of five City companies is also planning a similar approach.
If NFU Mutual, which has close ties with the National Farmers' Union, is floated on the stock market, the mutual's members could receive windfalls of up to £25,000 each.
But NFU Mutual is opposing any bids.
In a statement, the company said: “We are absolutely committed to mutuality.”
To convert NFU Mutual, 50% of the firms members must vote, with at least 75% of voters backing demutualisation.