For purposes of this guide:
Annual Reports: Refers to the Annual Report to Shareholders. These are written for current shareholders and potential investors. They go beyond financial statements and often provide a year-in-review. They can share a message from the CEO about the companies vision and direction. Often they are printed in a magazine type format and are sometimes referred to as a "glossy" report.
10-K: This is the year-end financial statement filing submitted to the Securities and Exchange Commission (SEC) for publicly traded companies in the United States.This is sometimes referred to by others as the annual report. The language in this report is geared toward explaining the numbers reported in the financial statements.