Second, Omer, Bedard, and Falsetta (2006) and Maydew and Shackelford
(2006) find that firms reduced or eliminated purchases of tax services from auditors
during the discussion of and subsequent to the passage of the Sarbanes-Oxley Act
of 2002 (SOX). Maydew and Shackelford (2006) posit that these self-imposed
restrictions potentially signal that these firms’ audits are of higher quality because
their auditors are not compromised by providing nonaudit services.