8-K (Material Event)

An 8-K is a form that publicly traded companies must file with the SEC (Securities and Exchange Commission—the government agency that oversees stock markets) whenever something important happens that could affect the stock price. Think of it as a company's way of saying "Hey, something big just went down." You'll encounter 8-Ks when researching stocks because they flag major events like executive departures, lawsuits, acquisitions, or earnings surprises. For example, if TechCorp's CEO suddenly resigned, they'd file an 8-K within four business days. These filings matter because they're required disclosures—companies can't hide big news—and they often move stock prices when investors learn about them. It's a useful tool for staying informed about what's really happening inside companies you're watching.