Nyambura Koigi is on the Board of Investments & Mortgages Bank Ltd. and I&M Holdings Ltd. In the past, Dr. Koigi held the position of Managing Director at Kenya Post Office Savings Bank and was also the Managing Director at Postbank NV.

In the past, Dr. Koigi held the position of Managing Director at Kenya Post Office Savings Bank. She was also the Managing Director of Postbank from 2005 to 2015. Koigi has worked in various capacities in the financial sector including banking, business development, and information communication technology. She has extensive training and experience in leadership, project management, product development, ICT, and Microfinance.