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 company's complete financial report card for the year—including revenue, expenses, profits, and risks. You'll find 10-Ks on the SEC's website or a company's investor relations page, and they're goldmines for serious investors who want the real story beyond marketing hype. For example, a retail company's 10-K might reveal that store traffic is declining even though sales look flat, giving you insight the quarterly earnings call glossed over. It's dense reading, but it's where companies have to tell the truth.