Mayor Francis Slay has bolstered his campaign fund with help from a law firm recently tapped to receive a tax break from City Hall.

Thompson Coburn — which in October was promised a $700,000 incentive package in exchange for keeping its office downtown — gave the mayor’s re-election account $20,000 on Nov. 26, according to filings with the state Ethics Commission.

The venerable law firm — a staple of the St. Louis legal community that included the late former U.S. Sen. Tom Eagleton as a partner — was weighing a move from Seventh Street to Clayton before Slay’s office offered a tax incentive to stay.

Another downtown law firm, Armstrong Teasdale, announced around the same time that they were leaving the city for the county.

Also on Nov. 26, Slay received $25,000 from a fund maintained by organized labor, and $5,000 from FUSE Inc., a downtown advertising firm.