During a walk on the California campus of chipmaker Nvidia in 2007, technology consultant Winifred Jiau invited a friend to form a “club” to share corporate financial secrets, the jury at her insider trading trial was told.

The friend was former Nvidia financial analyst Sonny Nguyen, who took the witness stand in Manhattan federal court to testify against Jiau yesterday. Nguyen told the jury he quickly lost faith in the “club” after he lost money on one of her stock tips.

Nguyen, 39, resigned from Nvidia on May 26 — the day before pleading guilty to criminal charges in what is a broad US government crackdown on insider trading. He is the third former associate of Taiwan-born Jiau, 43, to testify at her trial.

Closing arguments are expected today.