Boston Consulting Group, PwC and Mckinsey -three of the world’s largest consulting firms – received tens of millions of dollars in payments from an obscure firm in Dubai to help restructure Angola’s corruption-ridden oil sector, according to documents that reveal new details about suspicious money flows described in the globe-spanning Luanda Leaks investigation.

The Dubai firm, Matter Business Solutions, forwarded $31.2 million to Boston Consulting Group, $21.4 to PwC and $15.4 million to McKinsey as part of a 2017 project to modernise Sonangol, Angola’s state-owned oil company, according to bank statements and other documents seen by the Portuguese news outlets Expresso and SIC.

Billionaire Isabel dos Santos, the daughter of Angola’s longtime autocratic ruler, was Sonangol’s chief executive when the payments were made. Last year, as part of Luanda Leaks, journalists revealed that a personal friend of dos Santos owned the Dubai company. PwC and Boston Consulting were deeply enmeshed in Dos Santos’ business affairs, the report showed. They maintained those relationships long after many Western banks had cut her off amid questions about the source of her wealth. Boston Consulting helped run a failing jewellery business acquired with Angolan money. At the same time, PwC suggested ways to avoid Angolan taxes, and its accountants disregarded red flags about money movements between dos Santos entities that experts say should have raised alarms.

The Sonangol payments, by way of the Dubai shell company, highlight ongoing concerns about lax due diligence standards by consulting giants and light-touch regulations that allow foreign advisors to amass huge profits — no matter the money’s origin.

Learn more here.