The collapse of Greensill Capital has led to a series of investigations into how the company got into the financial mess it did and why alarm bells didn’t ring. But one investigation is noticeably conspicuous by its absence—why the company wasn’t properly regulated in the first place.

Neil Hodge is a freelance business journalist and photographer based in Nottingham, United Kingdom. He writes on insurance and risk management, corporate governance, internal audit, compliance, and legal...