FIN 48 disclosures rule requires public companies to disclose how much they have set aside to pay tax authorities if certain tax avoidance strategies are successfully challenged by the IRS. The disclosure requires the company to attach a dollar figure to tax-savings that could be vulnerable. The disclosure also has the effect of letting the IRS know which companies are taking a more aggressive tax position.

As a result of this disclosure, the Senate's Permanent Subcommittee on Investigations has issued 30 letters to companies asking for more details on the tax arrangements that led to their FIN 48 disclosures.