Yahoo's shares rose a whooping 17% after Microsoft chief exec Steve Ballmer hinted that a search advertising agreement between the two companies could be possible.

Ballmer told journos that, while there are no talks taking place at the moment, there could be in the future.

Speaking at a conference in Orlando, Ballmer said: "Perhaps there will continue to remain opportunities to partner around search".

"We are not in any discussions with them. We'll see. They want to remain independent. There are probably still opportunities around search."

"I think it would still make sense economically for their shareholders and ours."

Responding to a question fro an analyst at whether Microsoft was going to put in a new offer, Ballmer said: "We offered 33 bucks not too long ago and it's 11 and a half. So I don't know what price might have got the job done".

"It's clear that Yahoo did not want to sell the company. It did not want to sell when we offered 33 ... They probably think it's worth at least 33 today."

Talks between Microsoft and Yahoo finally broke down in July when Yahoo rejected the computing giant's offer to buy its search advertising business and sign a revenue-sharing partnership, but they had been on and off since January.

Yahoo isn't commenting.