This paper examines trends and factors that have influenced private-sector investment in infrastructure projects in Nigeria between 1990 and 2023. Despite growing interest in public–private partnerships (PPPs), private investment remains uneven across sectors such as transport, energy, information and communication technology (ICT), and municipal solid waste. Using project-level data from the World Bank's Private Participation in Infrastructure (PPI) database, the paper applies Ordinary Least Squares (OLS) and Quantile Regressions (QRs) to estimate the reasons behind the current investment level. The results suggest that ICT projects are not receiving significant investment, particularly on a small or medium scale, indicating sector-specific or constrained risks. Conversely, foreign sponsors are associated with higher investment values, though this only becomes apparent in large projects. Quantile regression further highlights the heterogeneous effects across the investment distribution. There are no consistent effects on multilateral support or on the type of project, such as Greenfield projects. These findings emphasise the necessity of targeted policy measures to encourage private investment in the ICT sector, which has historically experienced lower investment levels, and the requirement for more nuanced infrastructure planning approaches that consider project size diversity. The use of bootstrapped quantile regressions also helped to ensure robustness despite the small sample size of the projects. This research will be useful for policymakers, investors, and development financial institutions interested in investing in infrastructure in Nigeria.
Aidoo et al. (Fri,) studied this question.