Europe could pay approximately $20.9 billion to U.S. weapons suppliers if American companies maintain a 30% share of the EU's €60 billion defense fund for Ukraine across 2026-2027. The estimate is based on the Kiel Institute's finding that European donors already purchased about €3 billion from U.S. defense companies in the first half of 2026, with actual spending varying between $13.9 billion and $34.8 billion depending on U.S. system reliance.