Updated from 9:12 a.m. EST
scored a major win late Tuesday when the Federal Trade Commission dropped an antitrust suit against the company.
Early Wednesday, Rambus shares were recently up $8.70, or 34.5%, to $34.54.
The government's suit had contended that in the early 1990s, Rambus manipulated an industry group into adopting semiconductor standards for chips on which it already had patents pending.
In a statement, Rambus general counsel John Danforth called the dismissal of the suit "a fundamentally important step for Rambus as we seek to be fairly compensated for the use of our intellectual property."
In separate court cases, Rambus, which licenses intellectual property used in memory chips, has been battling to get major memory manufacturers such as
to pay royalties to it.
Micron spokesman Dave Parker said the latest ruling should have no effect on its own litigation against Rambus in a Delaware court.
"We believe that the administrative law judge failed to understand key points of fact and law presented by the FTC counsel at the trial," said Parker. "We're hopeful that on full review of the evidence and all the testimony, the commission will enter a final determination consistent with its earlier findings that served as a basis for bringing the suit against Rambus."
Parker noted that there is precedent for the FTC to reverse a decision by one of its administrative law judges. Moreover, the case could still be appealed within the FTC.
The commission's decision comes nearly two years after it launched an antitrust action against Rambus, in June 2002.
As the recent action shows, Rambus shares tend to spike and fall sharply based on momentum from the latest court ruling.
Only last week, the stock
sold off sharply on word that the European Patent Commission had revoked one of the company's patents. Analysts noted at the time, however, that the FTC decision was of far greater importance.