I&M Bank was founded in 1974 as a financial services company and later converted to a commercial bank.

I&M Bank is a wholly owned subsidiary of I&M Group PLC (previously known as I&M Holdings PLC), a public company, listed at the Nairobi Securities Exchange (NSE). The bank possesses a rich heritage in banking. Started in 1974, it evolved from a community financial institution to a publicly listed major regional commercial bank offering a full range of corporate and retail banking services.

From June 2013, I&M Bank shares are publicly traded in the Nairobi Stock Exchange through the acquisition of its entire shareholding by I&M Group Plc (previously known as I&M Holdings PLC), a publicly listed company.