Cotchett, Pitre & McCarthy filed a shareholder complaint Thursday against executives and directors of Wells Fargo, accusing them of turning a blind eye to the banking giant’s alleged use of “sham” tax shelters.

Filed in San Francisco Superior Court, the complaint alleges that Wells Fargo officials allowed the bank to avoid paying millions of dollars in federal income taxes by buying equipment from public entities and leasing it back to them. At the same time, the suit claims, Congress and the IRS were challenging these kinds of tax shelters.