The U.S. Supreme Court on Tuesday grappled with the burden of proof for corporate whistleblowers alleging discriminatory treatment as the justices heard an appeal from a fired research strategist at the investment arm of UBS.

Several justices seemed sympathetic to Trevor Murray’s claim that a lower court made it too hard for whistleblowers to prove they were retaliated against for bringing certain financial information to light. The case centers around lawsuits brought under the Sarbanes-Oxley Act, which prohibits employers from punishing whistleblowers.