The Supreme Court on Tuesday cemented the ability of prosecutors to pursue insider trading cases based on tips passed along among friends and family. The court, in a unanimous opinion written by Justice Samuel Alito, affirmed the conviction of Bassam Salman, who traded on information originally from his brother-in-law who worked as an investment banker at Citigroup.

Mr. Salman, who was convicted in 2013 and sentenced to 3 years in prison, had contended that evidence of a family relationship between the tipper and the tip recipient wasn’t enough to support a conviction. The high court disagreed, saying an earlier 1983 Supreme Court decision easily resolved the case against Mr. Salman. Justice Alito said the earlier high-court precedent “makes clear that a tipper breaches a fiduciary duty by making a gift of confidential information to a trading relative, and that rule is sufficient to resolve the case at hand.”