Olumuyiwa is a Chartered Accountant, a member of the Association of Chartered Certified Accountants (ACCA) and a Chartered Tax Practitioner. He has had extensive experience in Audit, Management Consulting and Financial Advisory Services, covering periods in Deloitte and Ernst & Young and the predecessor firm Olawale Coker & Co., which was a partnership of Olu and his late father Mr. F. C. O. Coker (the first president and one of the founding fathers of the Institute of Chartered Accountants of Nigeria), he was also the Group Managing Director of Lagos Water Corporation (the largest water utility in West and Central Africa) where he was responsible for the reform and restructuring of the utility and institutionalizing the framework for private sector participation in the sector in partnership with the World Bank and the IFC.
His professional background is in Audit and Assurance, Financial Advisory services, Tax, Strategy, and Consulting. As the Managing Partner of Mazars in Nigeria, Olu has been responsible for setting-up a new international brand "MAZARS" in Nigeria. Mazars was set up in Nigeria in 2011 as the top entity of the namesake international organization of audit, accounting, tax, regulatory and consulting services.