SAN FRANCISCO — Continuing the industry's fight against an initiative that raised law firm payroll taxes, Arnold & Porter and Coblentz, Patch, Duffy & Bass have filed new suits against San Francisco seeking to reclaim some of their 2011 taxes.

Passed in 2008 but modified by voters last year, Proposition Q established a 1.5 percent tax on profit distributions made to owners of so-called pass-through entities like law firms.