The Medical Information Bureau, commonly known as the MIB, is a member-owned organization that helps life and health insurance companies share limited underwriting information to detect errors, omissions, or potential fraud on insurance applications. When an applicant applies for individually underwritten coverage, participating carriers may query the MIB to see whether prior applications with other insurers reported certain medical conditions, hazardous activities, or adverse underwriting actions. The MIB does not maintain full medical records; instead, it stores coded entries representing significant underwriting-relevant information. These codes help underwriters decide whether additional medical evidence or clarification is needed before making an offer. The MIB operates under strict privacy and consumer-protection regulations, allowing consumers to request and correct their own MIB files. By reducing misrepresentation and improving risk selection, the Medical Information Bureau supports overall pricing accuracy and fairness in the insurance marketplace.

In daily practice, producers hear about the Medical Information Bureau when a carrier reports that an MIB code triggered further review. For example, an underwriter may say, "The MIB shows a prior application with possible cardiac history, so we've ordered an APS." Advisors sometimes encounter delays when MIB data does not match the current application or when older codes require clarification. When an unexpected decline or rating occurs, brokers may suggest that the client request a copy of their MIB report to verify accuracy and correct any errors. Training for new agents typically explains that material misstatements on one application are likely to be discovered by other participating carriers through MIB checks, reinforcing the importance of full disclosure. Compliance and privacy discussions also emphasize that MIB use is regulated, and clients have rights to access and dispute their data, similar to credit-reporting agencies.