Public-Private Partnership Investment Models, Blue Economy and Economic Growth in Nigeria

ABSTRACT: Public-private partnership investment remains a strategic financing instrument for closing infrastructure gaps, improving service delivery, and mobilizing private-sector capacity for development in Nigeria. At the same time, renewed attention to the blue economy has strengthened policy interest in fisheries, maritime transport, ports, marine logistics, coastal resources, and trade-linked economic activities. This study examined the effect of public-private partnership investment models and blue economy indicators on economic growth in Nigeria. Economic growth was proxied by real gross domestic product, while public-private partnership investment was proxied by private participation in infrastructure investment commitments. The blue economy was represented by agriculture, forestry and fishing value added and merchandise trade, while gross capital formation and inflation were included as control variables. Anchored on the Endogenous Growth Theory, the study adopted an ex post facto research design and relied on annual secondary time-series data covering 2000 to 2024. Data were sourced from the World Bank World Development Indicators, World Bank Private Participation in Infrastructure Database, and related official statistical sources. Data were analyzed using descriptive statistics, the Augmented Dickey-Fuller unit root test, the Autoregressive Distributed Lag bounds testing technique, the Error Correction Model, diagnostic tests, and stability tests. The findings revealed the existence of a long-run equilibrium relationship among the variables. Public-private partnership investment and agriculture, forestry and fishing value added exhibited negative and statistically significant effects on economic growth, merchandise trade had a negative but insignificant effect, gross capital formation had a positive and significant effect, while inflation had a negative and significant effect. The study concludes that PPP investment and selected blue economy indicators have not yet transmitted into the expected positive growth outcomes in Nigeria. The study recommends stronger project selection, transparent PPP contract governance, improved blue economy data systems, and better alignment of PPP projects with ports, fisheries, water transport, logistics, and export-oriented production.

KEYWORDS: PPP Investment, Blue Economy, Economic Growth, Gross Capital Formation, Merchandise Trade, Inflation, Real Gross Domestic Product.