A more thorough explanation:

Definition: Regulation FD, also known as Regulation Fair Disclosure, is a rule established by the Securities and Exchange Commission (SEC) in October 2000. This rule requires companies to disclose important information to all investors at the same time.

The purpose of Regulation FD is to prevent some investors from receiving information before others, which could give them an unfair advantage in making investment decisions. This information could include earnings reports, mergers and acquisitions, product discoveries, changes in auditors, and any other information that could impact a company's stock price.

Example: Let's say that a company is about to release its quarterly earnings report. Before Regulation FD, the company could have given this information to a select group of investors before releasing it to the public. These investors could have used this information to buy or sell the company's stock before the rest of the market had a chance to react.

However, with Regulation FD in place, the company must release this information to all investors at the same time. This ensures that everyone has access to the same information and can make investment decisions based on a level playing field.