Days after a bruising creditor call this August, money began moving across Mark Walter's financial empire. His asset management business, Guggenheim Investments, was showing signs of strain, and cash came in from investment vehicles controlled by the billionaire financier.

Previously unreported flows raise questions about whether Walter drew on insurance assets to help assuage financial troubles elsewhere. The unit at the centre of the creditor firestorm was waiting on four clients to pay more than $200mn booked in revenue the previous year. The clients all had links to Walter and to life insurance companies connected to him.

A whistleblower had flagged concerns about how Guggenheim Private Investments booked $275mn of revenue for 2024 services. KPMG warned of shortcomings in how revenues were recognised. Two insurers Walter owns revealed US prosecutors had subpoenaed them after misclassifying more than $20bn in investments.

Walter has since sold the Los Angeles Lakers and offloaded his stake in London's Chelsea Football Club. Credit rating agencies Fitch and S&P consider at least one linked insurer, Chicago-based Equi Trust, to be in a more difficult financial position, partly because of payments made to other parts of his empire.