The U.S. investigation into Mark Walter focuses on four intermediary organizations.

U.S. federal investigators are probing Mark Walter, focusing on four institutions. These four entities acted as intermediaries, handling loans issued to other companies within the business portfolio of the CEO of Guggenheim Partners' insurance enterprises. U.S. federal prosecutors and the Securities and Exchange Commission are investigating whether Walter and the companies he controls engaged in fraudulent activities, specifically concealing financial relationships during the process of borrowing billions of dollars from insurance firms. Investigators have narrowed the scope of their inquiry to ABS Capital, based in Miami, investment firm Amistad Financial, commercial real estate broker Bradford Allen, and Hudson Trading.