8-K (Current Report (Form 8-K))
The filing companies use to announce major events between quarterly reports.
What it means
An 8-K is the SEC's way of keeping investors informed about material events as they happen, instead of waiting for the next quarterly report. Companies file one for things like earnings releases, executive changes, acquisitions or other significant news. It is the fastest official signal that something important just happened.
Example
When a company hires a new CEO or agrees to a merger, it files an 8-K within a few business days.
Why it matters
8-Ks are where market-moving news often appears first in official form. Following a company's 8-K filings can tip you off to earnings, leadership changes or deals before the story is fully digested by the market.
See it on real stocks
Every stock analysis page shows 8-K alongside the other key metrics: