Greig is an experienced financial and accounting expert witness with more than 20 years of experience in resolving disputes involving accounting, valuation, and economic damages. His experience includes breach-of-contract and loss-of-profits claims, expropriations, minority-shareholder and joint-venture disputes, and claims arising following acquisitions and sales of businesses. Greig has testified in numerous international arbitrations under various institutions such as the ICC, AAA-ICDR, ICSID, and JCAA, as well as in ad hoc proceedings under UNCITRAL rules and free-trade agreements. He has also provided litigation consulting involving forensic accounting and financial investigations under various accounting and legal protocols. Greig is a Fellow of the Institute of Chartered Accountants in England and Wales.