Which act returned insurance regulation responsibility to the states in 1945?

The McCarran-Ferguson Act, passed in 1945, is significant because it explicitly recognized the states' authority to regulate the insurance industry. This legislation was a response to concerns that federal regulation of insurance could hinder the states' ability to regulate effectively and jeopardize the financial stability and consumer protection aspects of the industry.

The act essentially allowed states to continue overseeing and managing the insurance operations within their borders while providing that federal antitrust laws would apply to the insurance industry only to the extent that state regulations did not apply. This dual regulation framework helped maintain a level of consumer protection and localized oversight that many viewed as more beneficial than federal regulation alone could offer.

Understanding this context is crucial, as it highlights the balance between federal and state interests in insurance regulation during a critical period in American economic history. The other options listed pertain to different policy areas or do not exist as recognized pieces of legislation relevant to insurance regulation at that time.