Jennifer Blouin (University of Pennsylvania, Wharton School), Cristi A. Gleason (University of Iowa, Tippie Colege of Business), Lillian Mills (University of Texas, McCombs School of Business) & Stephanie Sikes (University of Texas, McCombs School of Business) have published What Can We Learn About Uncertain Tax Benefits from FIN 48?, 60 Nat’l Tax J. 521 (2007).  Here is the abstract:

FIN 48, Accounting for Uncertainty in Income Taxes, standardizes accounting for uncertain tax benefits and requires companies to disclose their tax reserve amounts. We summarize hand–collected disclosures related to tax reserves from 2005 through the first quarter of 2007. For the largest 100 non–financial, non–regulated firms, the reserve at adoption on January 1, 2007 is $78 billion excluding interest, or about two percent of assets. Of this $78 billion, an estimated $58 billion would affect earnings if ever released.