10-K (Annual Report)

A 10-K is the official annual report that every public company must file with the SEC (Securities and Exchange Commission, the government agency that oversees stock markets). It's basically a detailed financial snapshot showing how much money the company made, spent, and owes over the past year. You'll find 10-Ks on the SEC's website or a company's investor relations page, and they matter because they're audited by independent accountants—meaning they're way more reliable than a company's marketing materials. For example, if you're researching whether TechCorp Inc. is actually profitable, their 10-K would show you the real numbers instead of just their press releases. It's dense reading, but it's the most honest picture of a company's finances available to investors.