Why this hasn't landed yet
The finding, whatever it is, lands inside a live political fight where both sides have already decided what the IRA did. Supporters cite announced projects. Opponents cite the updated cost estimate of $1.2 trillion. A World Bank paper about additionality and identification strategy does not fit either narrative cleanly, so both sides will ignore it until they need a citation.
What happens next
Corporations that structured multi-year investment plans around IRA place-based credits now face a double uncertainty: a World Bank paper that may show the credits lack additionality, and a Tax Foundation testimony already before Congress arguing for partial repeal. Legal teams and government affairs shops at green manufacturers should be stress-testing their incentive assumptions before 2026 appropriations season.
The catch
The deepest problem with measuring IRA additionality is the counterfactual. You cannot observe the factory that wasn't built. Every prior study of US enterprise zones, including the Empowerment Zone program, produced contradictory results precisely because researchers couldn't agree on the comparison group. If the World Bank paper can't resolve that identification problem, the policy debate will simply continue citing whichever study reached the preferred conclusion.