SAN FRANCISCO – Rambus Inc. fell as much 78 percent Wednesday after it lost a $3.95 billion jury trial over its allegations that Micron Technology Inc. and Hynix Semiconductor Inc. conspired to prevent its memory chips from becoming an industry standard.

A jury in San Francisco by a 9-3 vote rejected Rambus’ claims that Boise, Idaho-based Micron and South Korea-based Hynix are liable for colluding to manipulate prices of dynamic random access memory, or DRAM, chips in violation of California antitrust law.

Jurors found by the same vote, after deliberating since Sept. 22, that the two companies aren’t liable for plotting to interfere with Rambus’ business relationship with Intel Corp. and driving the world’s largest chipmaker away from their collaboration on RDRAM, or Rambus-designed memory, that began in the 1990s.

“We are disappointed with this verdict as we believe strongly in our case,” Harold Hughes, CEO of Rambus, said in an emailed statement. “We do not agree with several rulings that affected how this case was presented to the jury and we are reviewing our options for appeal.”

Rambus said it would have made $3.95 billion in royalties without the alleged conspiracy. Under California law, a jury finding of antitrust damages in that amount would have been automatically tripled to $11.9 billion.

Trading in Rambus and Micron in New York was halted Wednesday after it was announced the jury had reached a verdict. After trading resumed at 3:40 p.m., Rambus fell as much as $14.04 to $4 and Micron rose as much as 25 percent to $6.84.

In the trial, which began in June, Rambus claimed Micron and Hynix acted as a cartel to derail Intel’s 1996 decision to collaborate on RDRAM as a solu- tion to a computer-memory bottle-neck. Hynix and Micron claimed the Rambus-Intel relationship was undone by Rambus’ hubris.