Bank Size and Bank Expansion in Kenya As Measured By Asset and Deposit Growth: Evidence from Panel Financial Data (2015–2024)

This study examines whether and why smaller commercial banks in Kenya expand more slowly than larger banks, using tier-segmented panel data (Tier I versus Tier IV) over 2015–2024. Bank expansion is proxied by annual asset and deposit growth. Explanatory variables capture size (log assets), cost efficiency (cost-to-income ratio), funding cost (interest expense-to-deposits proxy), asset quality (NPL ratio), and capital adequacy (core capital-to-RWA). Across pooled OLS models with heteroskedasticity-robust (HC3) standard errors, capital adequacy emerges as the most statistically robust and economically meaningful correlate of slower expansion: a one-percentage-point increase in the core-capital ratio is associated with approximately 3.29 percentage-point lower asset growth and 4.55 percentage-point lower deposit growth. Size is directionally positive but imprecisely estimated once controls are included, while efficiency does not mediate the size–growth association. The results highlight a growth–prudence trade-off in which prudential buffers materially constrain balance-sheet expansion for small banking segments. The paper contributes rare tier-segmented evidence from an African emerging market and offers implications for proportional regulation, capital calibration, and consolidation–competition trade-offs in Kenya.

bank size; bank growth; capital adequacy; cost efficiency

1. Arellano, M., & Bond, S. (1991). Some tests of specification for panel data: Monte Carlo evidence and an application to employment equations. Review of Economic Studies, 58(2), 277–297. [Google Scholar] [Crossref]

2. Basel Committee on Banking Supervision. (2019). Proportionality in bank regulation and supervision: A survey on current practices (BCBS Working Paper No. 36). Bank for International Settlements. [Google Scholar] [Crossref]

3. Beck, T., Demirgüç-Kunt, A., & Maksimovic, V. (2005). Financial and legal constraints to growth: Does firm size matter? Journal of Finance, 60(1), 137–177. [Google Scholar] [Crossref]

4. Berger, A. N., & Mester, L. J. (1997). Inside the black box: What explains differences in the efficiencies of financial institutions? Journal of Banking & Finance, 21(7), 895–947. https://doi.org/10.1016/S0378-4266(97)00010-1 [Google Scholar] [Crossref]

5. Central Bank of Kenya. (2023). Bank supervision annual report 2023. Central Bank of Kenya. [Google Scholar] [Crossref]

6. Demirgüç-Kunt, A., & Huizinga, H. (2010). Bank activity and funding strategies: The impact on risk and returns. Journal of Financial Economics, 98(3), 626–650. https://doi.org/10.1016/j.jfineco.2010.06.004 [Google Scholar] [Crossref]

7. Fang, X., Ospina, M., & Ruggiero, E. (2022). Bank capital requirements and lending in emerging markets. Journal of Banking & Finance, 138, 106473. [Google Scholar] [Crossref]

8. Judson, R. A., & Owen, A. L. (1997). Estimating dynamic panel data models: A practical guide for macroeconomists. Finance and Economics Discussion Series 1997-3. Board of Governors of the Federal Reserve System. [Google Scholar] [Crossref]

9. Kenya Bankers Association. (2025). State of the banking industry report 2025. Kenya Bankers Association Centre for Research on Financial Markets and Policy®. [Google Scholar] [Crossref]

10. Nyaundi, D. N. (2015). The effects of capital adequacy requirements on liquidity of commercial banks in Kenya (Master’s thesis). University of Nairobi. [Google Scholar] [Crossref]

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