Talks between Microsoft and Apple have been going on for weeks, Bloomberg said, citing two people familiar with the matter. The story noted that the negotiations may not conclude quickly and might still fall apart.
Microsoft's Bing search engine is trying to wrest market share from Google, the leader in Internet search.
Once seen as allies against Microsoft's dominance, Google and Apple find themselves competing on a number of fronts, including operating systems and the fast-growing smartphone market.
Apple is also working on ways to manage ads displayed on its mobile devices, a move that would challenge Google's advertising business, the Bloomberg story said.
(Reporting by Franklin Paul; Editing by Derek Caney)