Well, Peter Schweizer, who wrote about the allegedly shady dealings of the Clinton Foundation, is back at it with Secret Empires: How the American Political Class Hides Corruption and Enriches Family and Friends. The Obamas, Bidens, and Mitch McConnell are all detailed with their questionable business practices. For Obama, Schweizer noted that he used executive powers to attack certain industries, which allowed investment firms, who were run by his friends, to buy them at a reduced price (via Washington Examiner): https://townhall.com/tipsheet/mattvespa/2018/03/28/secret-empires-obamas-used-his-executive-powers-to-help-his-friends-investmen-n2463294