On November 8, 2019, President Uhuru Kenyatta signed into law the Finance Act 2019, effectively ending interest rate controls that had been in place for two years.
Sidian Bank moved swiftly to seize the moment, becoming one of the first small lenders to raise its lending rates after bearing the brunt of the cap.
In an internal memo signed by Chief Executive Officer Chege Thumbi, the lender announced new loan rates for its customers.
“Following the signing of the Finance Bill into law by the President, which, among other provisions, repeals Section 33B of the Banking Act that provides for the capping of bank interest rates, the bank has reviewed interest rates for various products based on the associated credit risk,” said Mr Thumbi.
With more than three decades of experience in banking, Mr Thumbi understood how critical raising interest rates was for Sidian, then a small bank. The interest rate cap regime had posed an existential threat.
Lacking large balance sheets to reassure depositors, smaller lenders typically attract funds by offering relatively higher returns and, in turn, charge borrowers higher rates. This explained Mr Thumbi’s readiness to move quickly and sign off on the rate review.
The uproar that followed was immediate. A local daily even questioned whether Mr Thumbi was the 'greediest' banker. The following day, Sidian’s then chairman, James Mworia, appeared to distance the board from the decision, saying management regretted the “unfortunate” issuance of the statement on revised interest rates.
It was perhaps the lowest moment in Mr Thumbi’s career. Yet he recovered, rebuilt his reputation, and went on to steer Sidian into a mid-sized lender, backed by deep-pocketed shareholders.
Last Friday, his nine-year tenure at the helm came to an end upon attaining retirement age, according to chairperson James Macharia, who announced that Mr Thumbi would be succeeded by John Okulo.
“Mr Thumbi has had a distinguished banking career spanning over three decades,” said Mr Macharia.
“During his tenure at Sidian Bank, he led a significant transformation of the business, including significantly growing the bank’s trade finance portfolio, increasing the branch network to fifty (50) and expanding digital banking and foreign exchange income streams-positioning the bank for sustainable growth and competitiveness,” added Mr Macharia.
One of Mr Thumbi’s key assignments when he was poached by the late Chris Kirubi from Credit Bank in August 2017 was to transition Sidian into a Tier II lender—defined by the Central Bank of Kenya as a bank with at least a one percent market share across assets, deposits, shareholder funds, and customer accounts.
Mr Kirubi was the majority shareholder of Centum Investments, which in turn owned Sidian Bank. In January 2023, Centum finalised a Sh4.3 billion deal to sell its stake in the lender to Nigeria’s Access Bank, paving the way for new investors.
Just a year after the acquisition of Centum’s stake by a motley group of investors, Sidian propelled itself into the ranks of mid-sized banks.
“Under his leadership, the Bank strengthened its operational capabilities, enhanced customer experience, and achieved significant business growth, culminating in its elevation to a Tier 2 Bank in September 2025,” said Mr Macharia.
Sidian has firmed its place as the fastest growing bank in the country by increasing its net profit for the year ended December 2025 six fold to Sh1.72 billion from Sh287 million posted a year earlier, lifted by piling cheap deposits.
The bank, upgraded to a mid-sized lender after doubling its market share in two years, grew its deposit base by 62.9 percent, or Sh28 billion, to Sh72.3 billion while its interest expenses rose at a slower pace, 23.1 percent, to Sh4 billion.
Sidian has benefited from recent partnership agreements with government agencies who have offered deposits that it has invested in Treasury bills and bonds.
Two weeks ago, Mr Thumbi, accompanied by the bank’s Head of Public Sector, John Nyongesa, paid a courtesy call on Kenyatta National Hospital CEO Richard Lesiyampe. The hospital later said the meeting explored areas of partnership aimed at supporting staff and enhancing service delivery.
The visit was one of several recent engagements with public sector institutions, even as it emerged that Sidian had secured lucrative State-linked deals and received a financing boost from its new shareholders.
Sidian’s growth has been underpinned by cash-rich accounts from public entities such as the Social Health Authority (SHA), the National Social Security Fund (NSSF), county governments, and other State agencies.
In November 2025, Nairobi Governor Johnson Sakaja directed public health facilities to transfer their accounts to Sidian Bank, giving the lender a significant boost in deposit mobilisation as its new owners push to cement its mid-tier status by 2028.
Earlier, in August 2024, Sidian was among six local lenders selected to handle payments under the Social Health Insurance Fund (SHIF), which is projected to process close to Sh200 billion annually, according to official estimates.
In a line-up dominated by Tier I heavyweights—including KCB Bank Kenya, Co-operative Bank of Kenya, Absa Bank Kenya, Equity Bank, and Diamond Trust Bank—Sidian stood out as the only Tier III lender at the time, raising questions about how it edged out larger and mid-sized competitors.
Mr Thumbi witnessed this transformation from the front row, even as speculation swirled around the political connections of the bank’s new shareholders.
He had taken over from Titus Karanja, who resigned as CEO to pursue other interests nine years ago.
At Credit Bank, Mr Thumbi is credited with steering the Simeon Nyachae-owned lender through a challenging operating environment.
An electrical engineer by training, he graduated from the University of Nairobi in 1989 and began his banking career at Barclays Bank in 1990 as a graduate trainee and teller at the Westlands branch. He later specialised in ICT and operations, playing a role in the bank’s early computerisation efforts up to 1994.
He subsequently worked at the Netherlands-based ABN AMRO, where he rose to head IT and MIS. In 2001, he joined Citibank as Senior Manager, Operations and Technology within Citigroup’s Kenyan operations.
In 2005, he moved to Commercial Bank of Africa as General Manager for Service Delivery, Technology, and Operations, where he was instrumental in the bank’s transformation, including the implementation of the T24 core banking system.
He rejoined Barclays Bank in 2008 as Director of Service Delivery, Change, and Technology before moving to NIC Bank in 2010 in a similar capacity. At NIC, he drove digital transformation and oversaw the expansion of the branch network.
In May 2015, he joined Credit Bank as CEO, before his eventual move to Sidian, where he leaves behind a lender that has set its eyes on Tier 1 status.
