Shares in online car marketplace Auto Trader Group rose more than 16% on their debut in London after Britain's largest ever private equity-backed listing.
The flotation gave the company a market value of £2.35 billion (€3.26 billion), making it also Britain's biggest listing of any kind since the government sold shares in Royal Mail in late 2013.
The company, which started out in the 1970s as a weekly magazine, went fully digital in 2013 under private equity owner Apax Partners after magazine circulation slumped.
It operates Britain's leading website for buying and selling new and used cars.
The firm, which also has an Irish operation, has focused its efforts on appealing to smartphone and tablet users, who run over 400,000 Auto Trader searches daily.
Auto Trader shares rose as much as 16.5% from the offer price of 235 pence to almost 274 pence.
The company raised about £437m in the offer, while Apax reaped proceeds of £926m from a sale of 59% of the company.
Including an over-allotment option for up to 15% of shares, Apax would be left with a holding of around 25%.
The size of the offering is larger than usual and far above Britain's listing requirements of 25%.
"They took the opportunity to reduce their overhang. They could have priced higher but they chose instead to do the bigger deal," said a source close to the deal, referring to the unusually large proportion of shares that the fund is selling.
Apax acquired 49.9% of Auto Trader from the Guardian Media Group in 2007 in a deal that valued the business at £1.35 billion. It subsequently bought the rest of the company in 2014 for £619m.
The listing follows an approach by US private equity firm Hellman & Friedman earlier this year with a potential £2 billion takeover offer.
Analysts raised questions about next steps for the brand, which focuses chiefly on the UK and Ireland. It generates £250m of revenue a year and employs 830 people.
"It's an online business that really does only one thing. Competitors such as eBay and Gumtree could impact that," said Mike Butler, analyst at data provider Eagle Alpha, adding that Auto Trader is seen by some car dealerships as expensive.
"One option would be a bolt-on business in the UK, like an insurance arm, to build the brand here. A new territory is a bigger undertaking," Mr Butler said.
Money raised from IPOs is down 16% globally as of March 12 this year compared with the same period of 2014, according to Thomson Reuters data, although the number ofo fferings is on a par.
Last year saw a spate of private equity-backed offerings, including British retailers Poundland and Pets at Home, as funds took advantage of surging stock markets to exit investments made before the crisis.
