Markets Move on Surprises, Not News
The price already contains a forecast — so only the gap between reality and that forecast moves it.
A company reports its best quarter ever — profits up 40%! You’d bet the stock leaps. Instead it drops 5% the same afternoon. How on earth can spectacular news push a stock down? Hold the puzzle. The answer is one of the most counterintuitive — and most clarifying — ideas in all of markets, and it builds directly on why news gets priced in.
The price already contains a forecast
From the last lesson, today’s price already reflects what people know — and that includes what they expect to happen next. If investors broadly expect a company to post great earnings, they’ve already bought in anticipation, lifting the price before the announcement. The good news is priced in.
So when the news finally lands, the question isn’t “was it good?” It’s “was it better or worse than what was already expected?” The forecast is baked into the price; only deviations from it are new information.
Only the surprise moves the price
Prices react to the surprise — the gap between what actually happened and what was expected:
- Result beats expectations → positive surprise → price tends to rise.
- Result matches expectations → already priced in → little movement.
- Result is good but worse than expected → negative surprise → price can fall, even on objectively great numbers.
That’s how a 40%-profit-growth company drops: the market had expected 50%. Traders call it “buy the rumor, sell the news” — people buy on the expectation and sell once it’s confirmed and there’s no upside surprise left.
Analysts expected $200 million in profit. The company reports $180 million — still a large profit, but $20 million below expectations. The surprise is −$20 million. Even though the company made money, it disappointed the forecast already baked into the price, so the stock falls. The raw number was good; the surprise was bad.
Markets grade on the curve of expectations, like a report card. A straight-A student who comes home with a 90 gets worried looks — a great score, but below what everyone expected. A student who always struggled and suddenly gets a 70 gets a celebration. Same two numbers, opposite reactions, because what matters is the result versus the expectation, not the result alone. Stocks react to news the same way.
Why the blowout quarter sank the stock: 1. For weeks, investors expected a fantastic report and bought ahead of it, pushing the price up — the good news got priced in. 2. The company reports profits up 40% — genuinely strong. 3. But the market had been expecting up 50%. Versus that forecast, 40% is a disappointment — a negative surprise. 4. Investors who “bought the rumor” now “sell the news,” since reality fell short of the baked-in expectation. The stock drops 5% — not because the quarter was bad, but because it was worse than already expected.
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