Form 10-K is the annual report a US-listed company such as Upwork Inc. files with the Securities and Exchange Commission after each fiscal year, with audited financial statements, a description of the business and key business metrics.
The 10-K is the most complete document Upwork Inc. publishes. Beyond the audited income statement, balance sheet and cash-flow statement, it describes how the marketplace works and makes money, lists the risks management is required to disclose, explains the accounting policies, including how revenue is recognised on marketplace fees, managed services and Upwork Payroll, and discusses the year in Management's Discussion and Analysis. Its Key Financial and Operational Metrics table gives gross services volume, active clients, GSV per active client, marketplace revenue and adjusted EBITDA for the year and the two years before it, which makes it the place where definition changes are explained and prior years restated.
What the 10-K does not do is report the fourth quarter on its own. The three quarterly 10-Qs cover the first nine months and the 10-K covers the year, so a fourth-quarter figure for a metric such as GSV has to be derived as the full year less the nine months to September, taken from filings of the same vintage so that a later restatement does not land in Q4 by accident. The GAAP lines have the same shape in XBRL, which tags the full-year value against the annual filing.
The audit opinion and the formal risk factors appear only here, which is why a reader checking the definition of a non-GAAP measure or a change in policy goes to the 10-K rather than the release.
How Upwork Insights uses it
The Pulse page takes each year's three 10-Q figures as reported and derives the fourth quarter from the 10-K as full year less the nine months to September, both from the same filing vintage. Active clients, a point-in-time count, are read from the 10-K's year-end columns directly. Method in methodology, section 4.