A 10-K is a comprehensive annual report that publicly traded companies in the United States must file with the Securities and Exchange Commission (SEC). It provides detailed information about a company's financial performance, including its income statement, balance sheet, and cash flow statement. The 10-K also includes information about the company's operations, risks, and management's discussion and analysis. The report is divided into several sections, such as Business, Risk Factors, and Financial Statements. Investors and analysts use the 10-K to assess a company's financial health and make informed investment decisions. It is an essential tool for transparency in the financial markets.