IMF flags tax revenue gap as Nigeria tests new tax reforms

Nigeria’s drive to boost government revenue through tax reforms faces a critical test of implementation, as the International Monetary Fund (IMF) warns that ambitious revenue targets often fail to translate into actual collections when policy changes are poorly executed and tax administration remains weak.

A study titled Understanding Over-Optimism in Tax Revenue-to-GDP Forecasts under IMF-supported Programs, which examined revenue projections between 2015 and 2024, found that programmes projected a median increase of one percentage point in the tax-to-GDP ratio by the third year, but the actual median gain was only 0.3 percentage point. This gap highlights a recurring problem in public finance: governments can build budgets around anticipated revenue gains from new taxes, higher compliance and administrative reforms that ultimately fail to materialise at the projected scale.

The IMF identified overestimated yields from tax measures, unrealistic assumptions about how revenue responds to economic growth, implementation weaknesses and errors in macroeconomic forecasts as major reasons collections fall short of projections.

More than half of the revenue expected from tax policy measures often failed to materialise, the study found, underscoring the risks of setting targets without sufficient administrative capacity and effective enforcement.

“When revenue measures are well-designed, fully implemented, and accompanied by high-depth revenue-related structural reforms, projected revenue gains materialise to a large extent,” the IMF noted.

The findings are particularly relevant to Nigeria, which began implementing a new tax framework in 2026 through four major laws covering tax administration, revenue collection and coordination among federal, state and local authorities.

The reforms are intended to simplify tax administration, harmonise the system, broaden the tax base, improve compliance and eliminate duplicate taxes. Their success will depend not simply on the provisions of the laws, but on whether revenue authorities can implement them consistently and collect what is legitimately due.

Businesses, however, continue to raise concerns about multiple taxes, levies and overlapping government collections, highlighting the gap that can emerge between reform objectives and conditions on the ground.

For the economy, revenue shortfalls have consequences beyond the failure to meet a fiscal target. When governments collect less than budgeted, they may be forced to delay capital projects, cut planned expenditure or increase borrowing to bridge financing gaps.

That can affect contractors, infrastructure providers, public-service delivery and the wider private sector, particularly when funding shortfalls lead to delayed payments or reduced public investment.

The opposite risk is equally important. If revenue authorities attempt to compensate for unrealistic targets through aggressive enforcement or additional charges on compliant businesses, the burden could increase without producing the expected sustainable improvement in collections.

The IMF findings suggest that expanding the tax base, improving administration and ensuring that approved measures are implemented effectively may deliver more reliable results than repeatedly raising revenue expectations.

For Nigeria, this means the performance of the new tax framework should be assessed against actual collections, compliance rates, administrative efficiency and the reduction of multiple levies, rather than the revenue targets announced at the beginning of the fiscal year.

The ultimate test is whether tax reform can increase predictable public revenue without weakening business activity or placing additional pressure on already stretched households and companies.

With government spending needs substantial and borrowing costs still a major fiscal concern, Nigeria cannot afford a persistent gap between projected and realised revenue. The country’s tax reforms will deliver their intended economic benefits only when legislative changes translate into effective administration, stronger compliance and measurable gains in public finances.