GLOSSARY // Fundamentals
Form 8-K
A Form 8-K is the SEC filing companies use to disclose material events between scheduled reports, generally due within four business days of the event. Earnings releases arrive as 8-Ks under Item 2.02, executive departures under Item 5.02, and major contracts under Item 1.01.
Because 8-Ks are event-driven, they are the filing most likely to move a stock the moment they hit. Many drop after the close or before the open, and the item number tells you the category before you read a word: 2.02 is results, 5.02 is officers and directors, 3.01 is a delisting notice, 8.01 is the catch-all.
At 8:47 pm an 8-K hits EDGAR under Item 5.02: the CFO has resigned effective immediately, no successor named. The press release, filed as an exhibit, says he is "pursuing other opportunities." The stock opens down 6% the next morning. Few single filings are a more reliable red flag than an abrupt CFO exit with no successor named.
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Educational only — not financial advice. Definitions simplified for clarity; markets are messier than definitions.