The REPO Implementation Act of 2025 amends the existing Rebuilding Economic Prosperity and Opportunity for Ukrainians Act to enhance the process of utilizing Russian sovereign assets for Ukraine's benefit. It incorporates the Porto Declaration, which calls on OSCE participating states to repurpose an estimated $300 billion in frozen Russian assets for Ukraine's recovery. A key provision allows the President to transfer Russian aggressor state sovereign assets into the Ukraine Support Fund for interest-bearing purposes without immediate confiscation. The Secretary of the Treasury is then mandated to invest these funds in interest-bearing U.S. obligations, ensuring that the principal generates additional revenue for Ukraine. To ensure consistent support, the bill requires quarterly obligations of at least $250 million from the Ukraine Support Fund for assistance to Ukraine. This mechanism ensures a regular and timely flow of financial aid derived from these assets, with the first obligation encouraged within 60 days of asset deposit. Furthermore, the Act expands its scope to international partners by requiring the President to submit reports detailing Russian sovereign assets held in G7, EU, Australia, and other foreign countries. It also expresses a Sense of Congress that the Secretary of State should lead a robust diplomatic effort to persuade these nations to repurpose at least 5 percent of their held Russian assets quarterly for Ukraine's reconstruction and support. Finally, the bill includes technical corrections to the original Act and broadens the scope of judicial review provisions, aiming to streamline and strengthen the overall implementation of asset repurposing efforts.