Which act mandated the conflict of interest rules for research analysts?

The Sarbanes-Oxley Act is the correct answer because it introduced important reforms to enhance corporate governance and financial disclosures, particularly in response to accounting scandals that affected investor trust. One of the Act's significant provisions included regulations aimed at addressing conflicts of interest for research analysts.

This legislation requires a clear separation between research functions and investment banking activities to mitigate any potential bias in research reports. By mandating that analysts disclose any conflicts of interest, the Sarbanes-Oxley Act seeks to ensure that investors can make informed decisions based on unbiased and accurate information.

Other acts, such as the Dodd-Frank Act, while also pivotal in financial regulation, focus on broader issues concerning systemic risk and consumer protection. The Investment Company Act primarily regulates investment companies and mutual funds. The Glass-Steagall Act, known for separating commercial and investment banking, does not directly address conflicts of interest related to research analysts. Thus, the Sarbanes-Oxley Act specifically targets the conflict of interest rules in the context of research analysts, making it the most appropriate answer.