A big company said it earned less than expected. Here's why the stock dropped so much.

Originally reported as: “TechCo shares slide after Q3 earnings miss analyst estimates”

A major company's stock fell sharply after it reported quarterly profits below what analysts had predicted. Even though the company was still profitable, the gap between expectations and results was enough to spook investors. This kind of reaction shows how much of a stock's price is built on expectations about the future, not just current performance. Earnings season, when companies report their results, tends to bring this kind of volatility across many stocks at once.