Piet started out as a lecturer at the University of Pretoria, and subsequently joined the South African Reserve Bank as an economic analyst. He joined Allan Gray Investment Counsel in 1991 as a portfolio manager and later moved to Investec Asset Management in 1995. Piet founded RECM, a financial services business, in 2003.

Piet co-invested into Maximus in 2024 and serves as a director. More importantly, he serves as a sounding board for Jan.