The Internal Revenue Service announced Tuesday that it would investigate the leak of records behind a blockbuster ProPublica story documenting how American billionaires pay minuscule amounts in taxes. The report used information from the tax payments and income reports of the likes of Jeff Bezos, Elon Musk, Warren Buffett, and Michael Bloomberg, but ProPublica’s reporters said they did not know the identity of the source that had provided them with the data. IRS Commissioner Charles Rettig said, “I share the concerns of every American for the sensitive and private nature and confidential nature of the information the IRS receives. Trust and confidence in the Internal Revenue Service is sort of the bedrock of asking people and requiring people to provide financial information.”