Born in Hlabisa and raised in Soweto, Sim holds degrees from Rhodes, Notre Dame (LLM, summa cum laude) and Wits. He joined Standard Bank in 2000, progressing to leadership roles, including Managing Director of Stanbic Africa and Chief Executive Officer of Personal and Business Banking. In 2017, he became sole Chief Executive. Sim serves on global boards, including the Institute of International Finance, where he is Vice-Chairman and Treasurer.