10-K (Annual Report (Form 10-K))
A public company's comprehensive annual report filed with the SEC.
What it means
The 10-K is the single most important document a public company files each year. It is a detailed annual report submitted to the SEC covering the business, its risk factors, management's discussion of results, and full audited financial statements. If you read only one filing on a company, read its 10-K.
Example
Apple's 10-K breaks out revenue by product (iPhone, Services, Mac), lists its risk factors, and includes audited financials for the fiscal year.
What to look for
Focus on three parts: the Risk Factors (what could go wrong), Management's Discussion and Analysis (how management explains the numbers), and the financial statements (the actual results). Comparing this year's wording to last year's often reveals changes in tone before they show up in the price.
See it on real stocks
Every stock analysis page shows 10-K alongside the other key metrics: