A Form 10-K is an annual report required by the U.S. Securities and Exchange Commission (SEC), that gives a comprehensive summary of a public company's performance. Although similarly named, the annual report on Form 10-K is distinct from the often glossy "annual report to shareholders", which a company must send to its shareholders when it holds an annual meeting to elect directors (though some companies combine the annual report and the 10-K into one document). The 10-K includes information such as company history, organizational structure, executive compensation, equity, subsidiaries, and audited financial statements, among other information.

Companies with more than $10 million in assets whose securities are held by more than 500 owners must file annual and other periodic reports, regardless of whether the securities are publicly or privately traded. If a shareholder requests a company’s Form 10-K, the company must provide a copy. In addition, most large companies must disclose on Form 10-K whether the company makes its periodic and current reports available, free of charge, on its website. Form 10-K, as well as other SEC filings may be searched at the EDGAR database on the SEC's website.

In addition to the 10-K, which is filed annually, a company is also required to file quarterly reports on Form 10-Q. Information for the final quarter of a firm's fiscal year is included in the annual 10-K, so only three 10-Q filings are made each year. In the period between these filings, and in case of a significant event, such as a CEO departing or bankruptcy, a Form 8-K must be filed in order to provide up to date information.

The name of the Form 10-K comes from the CFR (Code of Federal Regulations) designation of the form pursuant to sections 13 and 15(d) of the Securities Exchange Act of 1934 as amended.