Motley Fool analyst Andrew Tonner answers the question: What is a 10-K?

A 10-K is a financial document that all public companies file with the SEC each year. It's chock-full of investor must-haves, including financial statements and management discussion and analysis. It also includes the notes to financial statements, which are valuable for assessing a company's risk factors.

These are hefty documents. Apple's most recent 10-K was 20 pages long, while Google's was 18. It's worth taking the time to patiently sit down and read them carefully, though, because that's where great investments are found.

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