Under the virtually universally followed general rule, if a whistleblower loses their case, he/she does not have to pay the attorney fees incurred by opposing counsel. This general rule is especially true in whistleblower cases litigated within the U.S. Department of Labor. In these cases, there are strict rules preventing companies from ever obtaining any fees or costs from whistleblowers who lose their cases.
There are even limits on the number of sanctions given if a whistleblower files a frivolous lawsuit, in bad faith. In federal court, whistleblowers do not have to pay fees to a corporation if they lose their case. However, if a lawsuit is frivolous and pursued in bad faith, the whistleblower may be liable for sanctions. A losing party in federal court is often liable to pay court costs, which are very small when compared with attorney fees.
It is nearly impossible for a whistleblower who files under the SEC and IRS reward laws to be liable for attorney fees from his or her employer. This situation is especially true if they maintain their confidentiality.