Probe into secretive billionaire threatens Wall Street party

Antoine Gara and Lee Harris Aug 17, 2026 – 4.00pm Before Mark Walter amassed one of the biggest privately held sports and investment empires in the world, he was a little-known trader in an obscure market on Wall Street, far from the greed and glory of high-stakes corporate takeovers and audacious trades. Now Walter’s businesses are at the centre of a probe by US prosecutors into allegations that insurers he controlled lent to other parts of his investment empire without disclosing links to those loans. That investigation could further undermine confidence in a multitrillion-dollar private credit business that in the past decade has copied his strategy of tying insurance to alternative assets. Financial Times Subscribe to gift this article Gift 5 articles to anyone you choose each month when you subscribe. Subscribe now Already a subscriber? Fetching latest articles