The success or failure of a distressed debt investment strategy depends, in part, on the ability of a bankruptcy investor to prevent other investors in the same bankruptcy from obtaining information on its purchase and sale activity.  Rule 2019 of the Federal Rules of Bankruptcy Procedure has threatened to undermine the confidentiality of bankruptcy trading information.  At least some courts in the past two years have construed Rule 2019 to require bankruptcy investors to disclose the value of claims, the timing of purchase, amount paid and the fact of sales.  On April 26, 2011, the U.S. Supreme Court adopted amendments to Rule 2019.  This article details: relevant case law leading up to passage of the amendments; prior HFLR coverage of the extensive disagreement among courts regarding the level of disclosure required under the prior version of the rule; the key differences between the current version of Rule 2019 and the proposed amendment (Amended Rule 2019); the key definitions in Amended Rule 2019; what information must be disclosed under Amended Rule 2019; who must disclose it; and a new rule relating to identification of a chapter 15 debtor’s “center of main interests.”  For more on Rule 2019, see “Would the Expanded Disclosures Required by Proposed Amendments to Federal Rule of Bankruptcy Procedure 2019 Deter Hedge Funds from Investing in Distressed Debt? (Part Three of Three),” Vol. 2, No. 39 (Oct. 1, 2009); “How Can Hedge Funds that Invest in Distressed Debt Keep Their Strategies and Positions Confidential in Light of the Disclosures Required by Federal Rule of Bankruptcy Procedure 2019(a)? (Part Two of Three),” Hedge Fund Law Report, Vol. 2, No. 36 (Sep. 9, 2009); “How Can Hedge Funds that Invest in Distressed Debt Keep their Strategies and Positions Confidential in Light of the Disclosures Required by Federal Rule of Bankruptcy Procedure 2019(a)?,” Hedge Fund Law Report, Vol. 2, No. 34 (Aug. 27, 2009).