BRUSSELS—Amazon on Tuesday gained unconditional EU antitrust approval for its proposed $8.5 billion acquisition of U.S. movie studio MGM to help it to compete with streaming rivals Netflix and Disney+. The European Commission said the deal would not pose competition concerns in Europe, confirming a Reuters story on March 9. The EU competition enforcer said it had looked into overlaps between the world’s largest online retailer and MGM in audio-visual content and found that the combined market shares are low and that they have strong rivals. “The addition of MGM’s content into Amazon’s Prime Video offer would not have a significant impact on Amazon’s position as provider of marketplace services,” the Commission said. Amazon said it was pleased with the EU clearance. The U.S. Federal Trade Commission has a mid-March deadline to decide on the deal, a person familiar with the matter said. Analysts said the deal would boost Amazon’s …