* Aims to float 25-40 percent of shares in second half
* Listing seen as paving way to new Storebrand talks
* Analysts see IPO raising up $1.21-$2.97 billion
(Adds details, quotes, shares)
OSLO, March 11 Mutually owned Norwegian insurer Gjensidige said on Thursday it was planning an initial public offering (IPO) for the second half of 2010 to help its growth ambitions, raising the odds of a tie-up with peer Storebrand.
For years, Gjensidige has talked about listing. Its previous attempt to list on the Oslo bourse was abandoned during the global financial crisis.
Some analysts see the listing as a stepping stone towards a possible tie-up with fellow Norwegian insurer Storebrand (STB.OL), in which it has a 24.3 percent stake.
Storebrand, which specialises in life insurance, said a year ago it had tried and failed to merge with non-life insurer Gjensidige.
"A mutually owned company couldn't have merged with Storebrand today, so this (IPO) is an important step on the road to a possible merger with Storebrand," analyst Jan Gjerland in ABG Sundal Collier said.
Gjensidige is still Storebrand's single biggest shareholder.
The company said it would float 25 to 40 percent of its shares.
"We are starting the work now and plan to list in the second half. The formal application won't be sent until after the summer," Gjensidige spokesman Oystein Thoresen said.
Arctic Securities, DnB NOR DNBNOR.OL, Goldman Sachs (GS.N), and Pareto Securities were among the IPO advisers, Thoresen said.
"Gjensidige has been very, very cautious and very smart in not doing anything very quickly," analyst Matti Ahokas at Handelsbanken Securities said.
"They want to expand their product brand and buying Storebrand would be a natural step in that direction," he said.
Gjensidige said it would transform into a public limited group (ASA) from mutually-owned in connection with the listing.
Analysts contacted by Reuters expected an IPO to take place at 1.3 to 2.0 times book value, which at the end of last year stood at 22 billion Norwegian crowns ($3.7 billion), pricing the company at 28.6 billion to 44.0 billion. A deal to sell 25 to 40 percent could thus be worth 7.15 billion to 17.6 billion crowns.
Shares in Storebrand were up 1.1 percent at 48.2 Norwegian crowns at 1040 GMT, against a 0.2 percent drop on Oslo's main index .OSEBX, giving it a market capitalisation of 21.7 billion crowns. ($1=5.920 Norwegian Crown) (Reporting by Oslo newsroom; editing by Karen Foster)