Which law requires MLOs to protect personal financial information?

The Gramm-Leach-Bliley Act is the correct choice because it specifically addresses the protection of consumers' personal financial information. This law mandates that financial institutions develop privacy policies that inform consumers about how their personal data is collected, used, and disclosed. It requires that these institutions take appropriate measures to protect sensitive information from unauthorized access, thereby ensuring customer privacy and security.

In contrast, the other options focus on different aspects of real estate and lending regulations. The Real Estate Settlement Procedures Act primarily deals with transparency and fairness in the real estate settlement process but does not specifically focus on personal financial information protection. The Equal Credit Opportunity Act ensures that credit is granted without discrimination but does not address privacy standards for personal data. The Home Mortgage Disclosure Act is focused on requiring financial institutions to disclose information about their lending practices, especially in relation to discrimination and ensuring that credit is available to all, rather than the protection of personal financial information.