Financial development and income inequality in Africa

The study addresses the persistent rise in income inequality in Africa and its implications for achieving SDG-10 (reduced inequalities). While theory suggests that financial development can relax credit constraints and improve capital allocation for the poor, some countries with mature financial systems still experience high inequality (e.g., South Africa). The authors argue that prior work often relied on a narrow proxy of financial development (depth), overlooking other dimensions such as access, efficiency, and stability. They pose two research questions: (i) What are the effects of financial development on income inequality in Africa? (ii) How do the respective dimensions of financial development (access, efficiency, stability, depth) asymmetrically impact income inequality? To address endogeneity and dynamics in inequality, they adopt a System GMM approach using panel data for African countries.

The literature offers competing hypotheses on the finance–inequality nexus: (1) finance inequality-narrowing (improved access reduces inequality: Banerjee & Newman; Galor & Zeira; Johansson & Wang); (2) finance inequality-widening (benefits accrue to incumbents: Gimet & Lagoarde-Segot; Jauch & Watzka; Rajan & Zingales); and (3) nonlinearities such as the financial Kuznets (inverted U: Greenwood & Jovanovic; Shahbaz et al.) and a possible U-curve (Tan & Law; Chiu & Lee). Empirical evidence is mixed and often focuses solely on depth. Some studies find finance reduces inequality in certain contexts or periods (Jung & Vijverberg on China; Bumann & Lensink on liberalization), while others find no impact or inequality-widening effects (de Haan & Sturm; Hsieh et al.; Destek et al.). For Africa, results are likewise mixed: Adeleye et al. (2017) found no significant effect using domestic credit (depth), while Meniago & Asongu (2018) reported that disaggregated dimensions matter, with activity/efficiency helping but stability sometimes worsening inequality. Growing attention to financial inclusion suggests access can reduce inequality (Neaime & Gaysset; Omar & Inaba), though rapid inclusion may raise stability risks (Fouejieu et al.). The review motivates a multidimensional assessment of financial development—access, depth, efficiency, stability—for Africa.

The study is grounded in financial imperfection theory (Galor & Zeira), which emphasizes transaction and information frictions that constrain access to finance and can perpetuate inequality. The authors specify dynamic panel models where the dependent variable is the natural log of the Gini coefficient (income inequality), including its lag to capture persistence. Four model variants assess the overall financial development index and each dimension separately: access (bank branches per 100,000 adults), depth (domestic credit to the private sector as % of GDP), efficiency (bank cost-to-income ratio), and stability (bank Z-score). Control variables include education (primary school enrollment), age dependency ratio, trade openness (imports+exports % GDP), and mobile subscriptions per 100 people. Data cover 48 African countries from 1996–2018. Income inequality (Gini) is from the Global Consumption and Income Project (GCIP). Financial development dimensions are from the Global Financial Development Database (GFDD), and controls from the World Development Indicators (WDI). Estimation proceeds with pooled OLS as a baseline, followed by System GMM (Arellano–Bover/Blundell–Bond) to address endogeneity (e.g., lagged dependent variable, potentially endogenous finance indicators), unobserved heterogeneity, and dynamic panel bias. The System GMM uses internal instruments (differences instrumented with levels and vice versa), includes year effects, and reports diagnostic tests (Sargan for instrument validity; AR(1) for expected first-order serial correlation).

Descriptive statistics indicate substantial cross-country variation in financial development measures and controls over 1996–2018. Pooled OLS results show: (i) Access reduces inequality (bank branches coefficient ≈ −0.0207, p<0.05); (ii) Efficiency proxied by bank cost-to-income increases inequality (≈ +0.0235, p<0.05), implying that inefficiency is inequality-aggravating; (iii) Stability reduces inequality (bank Z-score ≈ −0.0240, p<0.01); (iv) Depth increases inequality (domestic credit ≈ +0.0305, p<0.05). Control variables display mixed signs depending on the specification. System GMM estimates, which the authors deem most reliable, corroborate dimension-specific effects: (i) Access lowers inequality (text reports ≈ −0.023% per 1% increase in branches; table shows significance consistent with this); (ii) Efficiency (cost-to-income) raises inequality (≈ +0.0204, p<0.01); (iii) Depth (domestic credit) raises inequality (≈ +0.0210, p<0.01); (iv) Stability (bank Z-score) lowers inequality (≈ −0.0187, p<0.01). Lagged inequality is significant, evidencing persistence. Diagnostic tests support instrument validity (Sargan p-values > 0.95 across specifications) and expected AR(1) rejection. Overall, financial development’s impact on inequality is heterogeneous by dimension: access, stability, and greater efficiency (i.e., lower cost-to-income) are associated with lower inequality, while greater depth (larger credit to private sector) is associated with higher inequality.

The findings directly address the research questions by demonstrating that the effect of financial development on income inequality in Africa is dimension-specific. Expanding access appears to relax financial constraints for the poor and vulnerable, improving capital allocation and reducing inequality. Greater stability builds trust in formal institutions and supports inclusive financial intermediation. Conversely, higher cost-to-income ratios (inefficiency) are linked to greater inequality, likely because costly intermediation limits lending to those who can afford it, excluding low-income users. Notably, greater financial depth—measured as domestic credit to the private sector—correlates with widening inequality, suggesting that expansion of credit volumes alone may disproportionately benefit incumbents or higher-income segments in contexts with frictions, weak inclusion, or unequal capabilities to access formal credit. The results harmonize with inclusion-centric theories and some prior evidence on access and stability, while contrasting with studies that equate deeper finance with inclusivity. The policy implication is that broadening the size of finance is insufficient; improving access, efficiency, and stability is critical for inclusive outcomes.

The paper contributes by providing a multidimensional assessment of financial development’s effects on income inequality for 48 African countries over 1996–2018 using dynamic panel methods. It shows that access, stability, and efficiency are inequality-reducing, whereas depth is inequality-increasing. The study cautions against policies that prioritize financial deepening alone and recommends comprehensive financial sector strategies that: expand affordable access to financial services, enhance intermediation efficiency (lower cost-to-income), and strengthen stability and resilience. Such a balanced approach is more likely to deliver inclusive distributional outcomes and support progress toward SDG-10. Future research could further unpack mechanisms (e.g., distribution of credit by firm size/household segment, role of digital financial services), explore non-linearities, and assess institutional moderators across African subregions.

The paper does not include a dedicated limitations section. Potential constraints implied by the design include reliance on available proxies for each financial dimension, use of aggregate country-level data, and sample coverage limited to African countries over 1996–2018.