A new report by congressional auditors finds that the costs for public companies to comply with a 2002 anti-fraud law have been higher than anticipated, providing ammunition to business interests that have been complaining about the law’s impact.

At the same time, though, the report by the Government Accountability Office released Monday raises concerns about the recommendations of an official advisory committee for exemptions from the law for smaller public companies. The scope of the proposed exemptions could damage the investor protection afforded by the Sarbanes-Oxley law that arose from the 2002 corporate scandals, the report says.