After retiring, Ma Shimin joined Jardine Matheson Group and worked in the Far East, starting from a low position, selling air conditioning systems and elevators. After working for 14 years, Ma Shimin left Jardine Matheson and established Davenham Investment Company with his partners. 1984 was appreciated by Li Ka-shing, a Hong Kong businessman, and bought his company. He was transferred to Hutchison Whampoa and became the managing director of Hutchison Whampoa. 1993 resigned and was replaced by Huo Jianning. During his tenure, he helped Hutchison Whampoa acquire Hongkong Electric and Husky Oil business in Canada, and also led Hutchison Whampoa to enter the mobile communication business, which indirectly contributed to the sale of its European mobile communication brand Orange in 2000 for more than HK$ 654.38+000 billion.
After leaving Hutchison Whampoa, Ma Shimin became CEO of Deutsche Bank Asia Pacific on 1994 and left on 1997. He also co-founded Distacom and invested in many mobile telecommunications companies around the world, including SUNDAY, which was later acquired by PCCW. In May 2007, he resigned as executive director of Huang Fei. Established GEMS, a private investment company, and served as the chairman of Macquarie Asia.
In 2006, he wrote an autobiography, Legion Soldiers: Five Years in the French Foreign Legion, describing his five-year career in the French Foreign Legion.