A shareholder in an insurance company on Tuesday sued a former executive who is running for U.S. Senate, claiming that his $28 million payout upon leaving his job was fraudulent and wasteful.

The claim against Republican candidate Mike McGavick resembles criticism from state Democrats, who have filed a federal campaign complaint about what they called his improper "golden parachute" after leaving Safeco Insurance Co.

McGavick rejected Tuesday's lawsuit as a baseless political attack.

"These allegations regarding my compensation are without merit and obviously politically inspired," he said in a statement. "It is sad that my opponents insist on dragging Safeco into the mean-spirited political process."

In a statement, Safeco downplayed the lawsuit and said McGavick's pay was extensively reviewed by company officials and outside advisers.

McGavick is seeking to unseat first-term Democrat Maria Cantwell.

The suit was filed by Emma Schwartzman, 27, a former waitress studying at the University of Washington. Schwartzman says her great-great-grandfather was a founder of General Insurance Co., a Safeco predecessor.

The suit says the agreement paving the way for McGavick to leave the company was "artfully drafted" to hide large amounts of money from shareholders. It seeks the return of McGavick's entire 2006 compensation, or whichever portion is found to be improper.

McGavick and Safeco are named as defendants, as are the company's board members, including former Democratic Gov. Gary Locke. The suit was filed in federal court in Seattle.

A statement released by Schwartzman's lawyers said neither the Democrats nor the GOP knew about the suit before it was announced Tuesday. Cantwell's campaign and the state Democratic Party declined to comment.