A case due to be heard in a federal appeals court on Tuesday could go a long way toward defining what exactly constitutes insider trading, potentially calling into question some of the most high-profile convictions won by prosecutors in their long-fought battle against the financial crime, the Wall Street Journal reports.

Todd Newman and Anthony Chiasson were part of a group of portfolio managers, fund analysts and company insiders who shared and traded on material nonpublic information about Dell Inc. and Nvidia Corp as part of a widespread $72 million insider-trading scheme, Bloomberg reports.