STOCKHOLM - AOL, a unit of Time Warner Inc., said Monday it is making a US$900-million (about 700-million-euro) cash bid to buy Swedish online marketing specialist TradeDoubler in an effort to improve its Internet advertising in Europe.

The bid offers 215 kronor ($30.60) per share for TradeDoubler, and the company's board has unanimously recommended its shareholders accept the offer, AOL said.

TradeDoubler shares soared nearly 12 per cent to 221 kronor ($31.46) on the Stockholm exchange.

Time Warner CEO Jeff Bewkes said the acquisition would help AOL become a bigger player on the European online advertising market.

"With AOL and, we have built a robust online advertising business in Europe, and TradeDoubler will help us accelerate the growth of this business," Bewkes said.

AOL said the acceptance period for the offer is expected to run from Jan. 22-Feb. 19, with about 20 per cent of TradeDoubler's shareholders already having accepted the bid.

Stockholm-based TradeDoubler was founded in 1999 and now has 334 workers with operations in 18 European countries. It had sales of 117 million euros ($151 million) in 2005.