A fired bank executive who became the first person to win protection under a federal law that shields whistleblowers — those who report corporate wrongdoing — only to see his victory overturned, suffered another setback in a federal appeals court Tuesday.

A three-judge panel of the 4th U.S. Circuit Court of Appeals did not reinstate David Welch to his job, ruling that he failed to explain how his employer’s alleged shoddy accounting practices could be considered a violation of federal law.