S-1 filing (IPO prospectus)

An S-1 filing is the official document a private company submits to the SEC (Securities and Exchange Commission) when it wants to go public and sell stock to regular investors for the first time. Think of it as a detailed prospectus—basically a company's honest sales pitch and financial playbook combined. You'll encounter S-1s when a company announces an IPO (initial public offering), and they matter because they contain everything you need to know before buying in: the business model, risks, financial statements, and how the company plans to use the money raised. For example, when TechStartup Inc. filed its S-1, investors could read exactly how the company made money and what could go wrong before deciding whether to buy shares on day one.