One claim, filed in April 2003, accuses Mayfield and PostX of conspiring to restrain trade by filing unfounded patent claims against Sigaba to slow Sigaba's market growth. The other claim makes similar allegations against PostX alone.
PostX filed patent infringement claims against Sigaba in September 2002. Sigaba officials said the company was cleared of any wrongdoing last November by the Federal Appeals Court in Washington, D.C., which unanimously upheld a decision by the federal court in San Francisco that a trial was unnecessary in the case.
"We're moving forward with our counterclaims to resolve any damage done to Sigaba by those meritless claims and erase any confusion caused by these bogus suits," Robert Cook, Sigaba executive chairman said in a statement.
A spokesperson for PostX said the company cannot comment on pending legal matters.