Banking Reforms, Efficiency and Competition in Ghana from 2008-2019

This paper examines the effect of the ongoing banking reforms on bank efficiency and bank competition within the efficient structure (ES) and the structure-conduct-performance (SCP) framework for the Ghanaian banking industry. Using an annual panel data of 21 Ghanaian banks from 2008-2019, we employed the nonparametric data envelope analysis (DEA) technique to estimate the level of bank pure-technical (PTE) and cost-efficiency (CE) while the Herfindahl-Hirschman Index (HHI) and the market share of lending (MSL) concentration ratios are employed as our proxies for the market power hypotheses. Further, the two-step system generalized method of moments is employed to estimate a panel model where the PTE, CE, HHI and MSL are regressed on bank-level factors while controlling for macroeconomic variables. Despite the remarkable improvements in bank efficiency in Ghana, the findings depict a worrying trend in bank competition resulting from the ongoing reforms. While increasing bank size and bank capital are found to have a positive relationship with bank efficiency and market power, a negative relationship between liquidity and bank efficiency and competition is reflected by the banks' inability to optimally utilize the excess liquidity flowing in from the other vulnerable financial sectors due to the ongoing banking crisis. We also document evidence on the high persistence of market power which suggest a declining bank competition in Ghana. Policy implications for the Ghanaian banking industry regulation are discussed.本文基于有效结构（Efficient Structure, ES）与结构-行为-绩效（Structure-Conduct-Performance, SCP）分析框架，考察当前银行业改革对加纳银行业的银行效率与银行竞争的影响。本研究使用2008至2019年间加纳21家银行的年度面板数据，采用非参数数据包络分析（Data Envelopment Analysis, DEA）方法估算银行纯技术效率（Pure-Technical Efficiency, PTE）与成本效率（Cost Efficiency, CE）水平，并以赫芬达尔-赫希曼指数（Herfindahl-Hirschman Index, HHI）及贷款市场份额（Market Share of Lending, MSL）集中度比率作为市场势力假说的代理变量。进一步地，本研究采用两步系统广义矩估计法构建面板模型，将纯技术效率、成本效率、赫芬达尔-赫希曼指数与贷款市场份额作为被解释变量，对银行层面特征变量进行回归分析，同时控制宏观经济变量的影响。尽管加纳银行业的效率已实现显著提升，但研究结果显示，当前的银行业改革引发了令人担忧的银行竞争态势。研究发现，银行规模扩张与资本水平提升与银行效率及市场势力呈正相关关系；而流动性与银行效率及竞争则呈负相关关系，这源于当前银行业危机背景下，加纳银行无法最优利用从其他脆弱金融部门流入的过剩流动性。本研究还证实市场势力具有高度持续性，这表明加纳的银行竞争程度呈下降趋势。本文最后讨论了针对加纳银行业监管的政策启示。