Entrepreneur Sir Peter Wood is to make £360m from selling his stake in the insurer esure, which is being bought by a private equity company.
The insurer, which also owns Shelia's Wheels, is being bought for £1.2bn by Bain Capital.
Sir Peter, who founded esure, will reinvest £50m into the business and will remain as chairman.
The deal was announced alongside interim results showing a £14m hit from the cold weather earlier in the year.
More customers made claims for burst pipes and problems with their cars caused by the "Beast from the East".
Profits in the first six months of the year fell 20% to £36.1m.
But Sir Peter said the business was delivering "profitable growth" and described the takeover by Bain as "a great outcome for shareholders".
It means that the shares, which were floated at 290p in March 2013, will no longer be listed on the stock market, assuming the deal is completed.
Bain is offering 280p a share, although this cannot be compared directly with the original price as the company has bought and sold GoCompare since then.
The offer price is a 37% premium to the price before news of the deal emerged.
The shares were trading 3.5% higher on Tuesday at 277p,
Sir Peter is known for revolutionising the insurance market when, in the 1980s, he started Direct Line, backed by Royal Bank of Scotland, allowing customers to buy insurance directly over the phone.
At the time, a payout of £18m to him was described as "obscene".
His stake was later bought out by RBS and he went on to create esure with the banking of HBOS, before it was taken over by Lloyds during the financial crisis. Sir Peter led £185m a management buyout from Lloyds in 2010.
When esure was floated in 2013, he made nearly £200m.
He spends his holidays in Palm Beach. According to reports, he owns one of the world's largest collections of Margaret Thatcher's clothes.
Nicholas Hyett, equity analyst at Hargreaves Lansdown, says: "A formal offer from Bain Capital at a sizeable premium to market price means esure will, in all likelihood, be leaving the stock market soon.
"With scope to improve the esure and Shelia's Wheels brands, as well as further improvements in underwriting, we can see the attractions for Bain.
"For shareholders, the deal means the benefits of those improvements will be landing in bank accounts a little earlier than expected."