Form D is a required filing with the Securities and Exchange Commission (SEC) that companies use to inform the SEC about their sale of securities without going through a full registration process. When a startup wants to raise funds by offering stock, they can choose to file Form D instead of conducting an initial public offering (IPO) or selling stock to the general public. Practically speaking, private stock offerings necessitating the use of Form D are the only way that startups can sell stock. By filing Form D, companies notify the SEC that they are making a private offering of securities to a specific group of investors.

Filing Form D is important because it helps companies comply with securities laws and regulations. It ensures that companies follow the proper procedures when selling securities and provide necessary information to the SEC. This form allows companies to raise funds from accredited investors or qualified institutional buyers without undergoing the lengthy and complex registration process.

Companies must file Form D within 15 days after the first sale of securities in their offering. The filing is done electronically using the SEC's EDGAR system, which is a platform for submitting and accessing financial reports and other required filings.