Memory design company Rambus said that it is "co-operating" with a Federal Trade Commission (FTC) investigation, after industry complaints that it has abused its dominant position.
Sources within the FTC say that it is considering an antitrust lawsuit against the company.
There have been unconfirmed reports that the FTC is looking into the possibility of an injunction which would block Rambus from collecting royalties on fast types of memory chips.
Rambus licenses its own technology and has been claiming that its patents cover most other types of fast memory chips.
Micron Technology and Infineon Technologies are among the companies that have challenged the Rambus claims. They have suggested that Rambus is charging more than the industry can sustain to license the technology.
Shares in Rambus fell five per cent as investors became concerned that a possible FTC lawsuit could prevent the company from collecting royalties on some of its key patents from chipmakers that have yet to agree to a licence.
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