The jury in the trial of Raj Rajaratnam, who is accused of insider trading, will have to be begin its deliberations again.It comes after a juror was dismissed from the case for medical reasons.
The founder of the Galleon hedge fund is accused of trading on inside tips about companies and benefiting to the tune of $63.8m (£38.6m).
Mr Rajaratnam, who is on trial in New York, insists he is innocent and only used publicly available information.
Jurors had deliberated for six days prior to Wednesday.
"You must disregard your earlier deliberations and begin your deliberations anew," US District Judge Richard Holwell told the jurors.
Another juror will replace the dismissed juror he added.
Six alternate jurors, who sat through seven weeks of evidence, were specifically chosen in case such incidents happened.
Mr Rajaratnam himself was absent from the courtroom in Manhattan earlier this week because of treatment on an infected foot.
He faces up to 25 years in prison if convicted of securities fraud and conspiracy charges.