Final answer:
The rule that addresses required disclosures to investors in a corporate transaction is Rule 14a-9, which prevents false or misleading statements in proxy materials and is enforced by the Securities and Exchange Commission.
Step-by-step explanation:
The rule addressing the required disclosures to investors in a corporate transaction is known as Rule 14a-9. This rule, promulgated under the Securities Exchange Act of 1934, prohibits false or misleading statements in proxy solicitation materials. Specifically, Rule 14a-9 requires that all facts material to the vote of the shareholders be presented accurately and without omission of important information. Not complying with this rule can lead to enforcement actions by the Securities and Exchange Commission (SEC).
Other rules mentioned, such as Rule 144A, Rule 10b-5, and Rule 506(c), serve different purposes within securities regulations. Rule 144A deals with the resale of private securities to qualified institutional buyers, Rule 10b-5 pertains to fraud in connection with the purchase or sale of securities, and Rule 506(c) allows for general solicitation or advertising to sell securities provided that all purchasers are accredited investors.