The biggest privately-owned insurance company in the UK is being put up for sale for an estimated $5.95 billion ($3 billion).

Towergate's executive chairman Peter Cullum, who ten years ago worked as marketing director for specialist insurer Hiscox but left in 1997 to set up Towergate, will collect a personal windfall of around $4b if the private firm is sold for the projected price.

The firm was formed in 2005 by the merging of two businesses set up by Mr. Cullum, 56.

Towergate made $94.4m ($187.2m) profit last year, a 51 percent increase. Its business is focused on niche insurance products that include coverage for caravan parks and holiday homes.

According to UK newspaper reports private equity companies Blackstone, Charterhouse, TA Associates and Candover have been referred to Towergate's financial advisor Lexicon Partners to discuss a possible sale.

Mr. Cullum, who has a 65 percent stake in the business, is said to be reluctant to see Towergate sold for less than $3bn.

Towergate employs 3,500 staff in the UK and, according to a London report around 2,000 of those employees are in line for a $45,000 ($89,275) windfall through an employee share plan.

The talks on a possible sale of part or all of Towergate are at an early stage, said Andy Homer, of Lexicon.

Quoted in the Financial Mail, he said all options were being considered.

Towergate is Europe's largest independent insurance business, having made more than 100 acquisitions of smaller rivals. That trend is set to continue with plans for $460m ($912.5m) to acquire independent financial advisors.

Mr. Cullum is a noted philanthropist and owns a charitable trust that funds children's charities. He paid half his $9.2m ($18.25m) bonus into the trust last year, according to UK newspaper The Guardian.

The true value of Towergate appears to be in debate as bankers have placed the $3b tag on the company, but a refinancing of the company last year estimated its value at $1b ($1.983b)

Bermuda-based companies have been eyeing up acquisitions in the UK with reinsurer Validus Re in the process of buying Lloyd's of London's Talbot Underwriting in a reputed $400 million deal and last year Bermuda-based Catlin bought its smaller rival Wellington Underwriting for $591 million ($1.172b).