Twitter has acquired over 900 patents from IBM. The deal, which includes a cross-license agreement, was made last month, but the two companies have now formally announced it.

IBM has received more patents in the U.S. than any other company for 21 consecutive years.

Twitter Legal Director Ben Lee said, “This acquisition of patents from IBM and licensing agreement provides us with greater intellectual property protection and gives us freedom of action to innovate on behalf of all those who use our service.”

Ken King, General Manager of Intellectual Property for IBM, said, “We are pleased to reach this agreement with Twitter because it illustrates the value of patented IBM inventions and demonstrates our commitment to licensing access to our broad patent portfolio. We look forward to a productive relationship with Twitter in the future.”

A couple months ago, in an update to its S-1, Twitter revealed that IBM had issued a letter to the company alleging that it was infringing upon at least three of its patents, but “inviting” Twitter to negotiate a “business resolution”.

Those particular patents were for “Efficient retrieval of uniform resource locators,” “Method for presenting advertising in an interactive service,” and “programmatic discovery of common contacts.”

The companies did not reveal the terms of the deal.

The news recalls when Facebook bought 750 IBM patents a couple years ago.

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