Microsoft, which just bought patents from AOL for $1 billion, is now turning around and selling most of them to Facebook for $550 million.

Microsoft and Facebook said Monday that Facebook is buying about 650 of the 925 AOL patents and patent applications Microsoft bought.

Facebook will also get a license to use the rest of the AOL Inc. patents. Similarly, Microsoft Corp. will get a license to use the patents Facebook is buying. This part of the arrangement amounts to an agreement between Facebook and Microsoft not to sue each other over any of the AOL patents.

Microsoft says the deal enables it to recoup half the cost of the AOL deal while reaching its goals for the purchase.