For the first five years Microsoft is to pay Yahoo! 88% of revenue it makes from search ads placed on Yahoo!'s sites and Yahoo! is to exclusively sell premium search ads on both companies' sites.
According to a regulatory filing by Yahoo! yesterday the five-year mark will bring three possibilities affecting the proportion of revenue Microsoft will give Yahoo!.
If neither company seeks to alter the terms, Yahoo!'s share will go up to 90% after five years.
If Microsoft decides to reclaim control of premium ad sales on its own sites it will have to pay Yahoo! 93% of the revenue it makes from search ads placed on Yahoo!'s sites.
In this case Yahoo! could overrule Microsoft's wish and maintain its exclusivity, but it would have to accept its revenue share falling to 83%.
The filing also shows that Microsoft will pay Yahoo! $50m each year for the first three years to help it cover the costs of establishing the partnership.
Microsoft is to hire at least 400 Yahoo! employees and their transition will be managed by an additional 150 Yahoo! employees to be selected by the two companies.