The fast-growing classified ads company, whose brands include France's Leboncoin, Brazil's OLX and Britain's Shpock, was spun off from media firm Schibsted, selling so-called class B shares at 78 Norwegian crowns each.

The B shares hit 88.0 crowns at 1115 GMT, up 12.8 percent, while its A shares - distributed to Schibsted shareholders and carrying greater voting rights - traded at 88.9 crowns.

Overall the group achieved a market value of 60.2 billion Norwegian crowns (5.41 billion pounds).

It was the Nordic nation's most valuable new listing since 2006 and the fourth-biggest overall, exceeded only by oil firm Equinor, telecoms group Telenor and solar industry supplier REC Silicon.

Adevinta has set its sights on mergers and acquisitions, CEO Rolv Erik Ryssdal told Reuters last year.

The separation from Schibsted makes it easier for investors to value Adevinta by comparing with listed peers such as the UK's Autotrader and Rightmove, Australia's REA Group and New Zealand's TradeMe.

"I regard the new setup as a licence to expand," Ryssdal told Reuters shortly after ringing the bell that marks the start of trade on the Oslo stock exchange.

While the company could grow as part of Schibsted, it will now have greater flexibility to borrow or issue new shares to pay for takeovers. "With this setup we are even better positioned to take the lead in the consolidation of the industry," Ryssdal said.

Shareholders were given one Adevinta A share for each Schibsted A share, and one B share for each Schibsted B, although the two share classes will eventually merge.

Schibsted and Blommenholm Industrier will maintain their majority holding in Adevinta.

From a modest start publishing newspapers, Schibsted built fast-growing websites and apps in 22 countries, allowing private and professional users alike to advertise anything from second-hand items to cars, homes or jobs.

Schibsted will keep its newspapers and classified ads units in the Nordic region.

The launch in 2016 of Facebook Marketplace weakened Schibsted's share price, but it rebounded on signs that the entry of such global players had so far had little impact.

"The most important thing is to develop our own services and be prepared," Ryssdal said. "The competition may come from many different places."

(Writing by Terje Solsvik; Editing by Mark Potter and David Holmes)

By Nerijus Adomaitis and Terje Solsvik