Level 4 · Module 1: How Capital Markets Work · Lesson 2
Why Stock Prices Move
Stock prices do not move in response to reality — they move in response to the gap between reality and prior expectations. If the market expected a company to earn $2.00 per share and it earns $2.00 per share, the price barely moves; that outcome was already priced in. If it earns $1.80, the price falls even if $1.80 is historically good. The price already contained a forecast, and understanding that forecast — the consensus expectation — is more important than understanding the company's actual results.
Building On
In the previous lesson we established that the secondary market is where price discovery happens. Now we examine the mechanics of that discovery — specifically, what information actually moves prices and why 'good news' sometimes isn't.
Why It Matters
On February 2, 2022, Meta reported Q4 2021 earnings. Revenue was $33.7 billion — up 20% year over year. By most measures, a strong quarter for a company of any size. The stock fell 26% the following day, erasing roughly $230 billion in market cap in a single session. The cause was not the Q4 results. It was guidance: Meta projected Q1 2022 revenue of $27 to $29 billion, well below analyst consensus of $30.2 billion. The market had priced in a number that Meta said it would not deliver, and it repriced violently.
This is the expectation mechanism in action. Analysts spend enormous energy building models that estimate a company's future earnings. Those estimates aggregate into a 'consensus' — a widely shared forecast. When a company reports results, the market is not reacting to those results in isolation; it is reacting to the difference between results and consensus. A company that earns $4.00 per share when consensus was $3.50 will typically see its stock rise, even if $4.00 is not a record. A company that earns $3.80 when consensus was $4.10 will fall, even if $3.80 is the best result in the company's history.
Interest rates interact with stock prices through the discount rate. Every stock can be modeled as the present value of its future cash flows — money the company will generate years from now, discounted back to today. When interest rates rise, the discount rate rises, which makes future cash flows worth less in today's dollars. Growth stocks — companies whose earnings are heavily weighted toward future years — are especially sensitive to this. Between January and October 2022, as the Federal Reserve raised rates from near zero to 3.75%, the Nasdaq Composite fell roughly 33%. Many high-growth technology stocks fell 60 to 80 percent. The underlying businesses had not collapsed; the math of discounting had changed.
Buybacks and dilution move prices in opposite directions. A buyback occurs when a company uses cash to repurchase its own shares from the secondary market, reducing shares outstanding — the same earnings spread over fewer shares means higher earnings per share, which generally lifts the stock. Dilution is the reverse: issuing new shares (for an acquisition, an employee compensation plan, or a capital raise) increases shares outstanding, spreading earnings over a larger base. Shareholders who do not understand this will be confused when a company announces record profits and the stock barely moves — while another company announces a $10 billion buyback and jumps 5% on no earnings news at all.
A Story
Diego's Lesson
Diego Restrepo had been saving since he was thirteen. By the time he was sixteen, he had $3,400 in a custodial brokerage account his father had opened for him. He had been reading earnings reports for six months, watching YouTube breakdowns of balance sheets, and he was confident he understood how this worked.
In October 2023, Diego bought 14 shares of a mid-sized software company called Vertex Analytics — a real company in his mind, though he had invented the name — at $241 per share. Total investment: $3,374. He had done the analysis. Revenue was growing 28% annually. Gross margins were 74%. The company had just won a major contract with a Fortune 500 client. Diego told his father: 'The next earnings report is going to be great. This thing is going to pop.'
Earnings day came. Vertex reported $312 million in revenue, up 31% year over year — beating Diego's own estimate. Earnings per share of $1.14, also a beat. The contract win was confirmed in the press release. Diego refreshed his brokerage app at 4:02 p.m. The stock was down $19.80 in after-hours trading.
He called his father immediately. 'Dad, the numbers were good. Why is it down?' His father did not know. Diego stayed up until midnight reading analyst notes. He found the answer buried in the earnings call transcript. Vertex's CFO had guided Q4 revenue to $318 to $322 million. Analyst consensus had been $331 million. The company beat Q3 — and missed Q4 guidance expectations by roughly $10 million on the low end.
The market had already priced in $331 million for Q4. When the CFO said $318 to $322 million, the market immediately repriced the stock to reflect that lower trajectory. The excellent Q3 results were irrelevant — they were already embedded in the prior price. The new information was the guidance miss, and the stock adjusted for that information alone.
Diego sold nothing. He sat with the position for three weeks, watching it drift from $221 to $214. Then something shifted in the broader market — the Federal Reserve signaled it might pause rate hikes. High-growth software stocks rallied. Vertex moved from $214 to $248 in nine days without releasing any new company-specific information. The same stock, the same business fundamentals, a 16% price change driven entirely by a change in macro sentiment and the discount rate applied to future earnings.
Diego kept a journal of that period. His entry from the day Vertex hit $248: 'The stock went up because people think rates might stop going up. Not because Vertex did anything different. I thought I was analyzing a company. I was actually analyzing a claim about the future, inside a market full of other people making claims about the future. My claim was less important than theirs.'
He did not sell at $248 either. He held for another year, through a secondary guidance miss and a subsequent rally. When he finally sold at $267, he had made about $364 on the position — roughly 11% over fourteen months, during which the stock had swung more than 30% in both directions. The lesson had cost him nothing in money and everything in certainty.
Vocabulary
- Earnings report
- A quarterly disclosure in which a public company reports its revenue, expenses, and profit. The report is compared against analyst consensus estimates, and the gap between actual results and expectations typically drives price movement.
- Guidance
- Forward-looking statements from company management about expected future revenue, earnings, or other metrics. Guidance misses — projecting results below analyst consensus — often move stock prices more than the current quarter's results.
- Valuation multiple
- A ratio that expresses how much investors are paying per unit of earnings or revenue — for example, price-to-earnings (P/E) or price-to-sales (P/S). Multiples expand when sentiment is positive and compress when sentiment turns negative or rates rise.
- Discount rate
- The interest rate used to calculate the present value of future cash flows. A higher discount rate makes future earnings worth less today, which reduces the theoretical value of stocks — especially growth stocks whose earnings are far in the future.
- Buyback
- A share repurchase program in which a company buys its own stock from the secondary market. This reduces shares outstanding, increases earnings per share, and typically lifts the stock price.
- Dilution
- An increase in shares outstanding — through new share issuances for acquisitions, compensation, or capital raises — that reduces each existing share's ownership percentage and typically weighs on the stock price.
Guided Teaching
Start with a simple thought experiment. Tell the student: 'A company reports that it earned $2 per share this quarter. Is that good or bad?' The correct answer is: it depends entirely on what the market expected. If consensus was $1.60, that's a strong beat and the stock likely rises. If consensus was $2.40, that's a miss and the stock likely falls. The number means nothing in isolation.
Ask: What does it mean for something to be 'already priced in'? Work toward this definition: the stock price at any moment already incorporates the market's best guess about future earnings, future growth, future macro conditions. New information only moves the price if it changes those expectations. Old information — even if it's genuinely impressive — is already in the price and does nothing.
Walk through the Meta example carefully. Revenue up 20%, stock down 26%. Ask the student to identify what new information arrived on earnings day that moved the price. The answer is the Q1 guidance — specifically, the gap between what Meta projected ($27–29B) and what analysts had modeled ($30.2B). That ~$1–2 billion gap on quarterly revenue caused $230 billion of market cap to evaporate overnight.
Introduce the discount rate mechanism. Use a simple example: a company will earn $10 million in five years. At a 5% discount rate, that's worth roughly $7.8 million today. At a 10% discount rate, it's worth roughly $6.2 million today. Same future earnings; $1.6 million difference in present value — just from the rate change. Now scale that to a trillion-dollar company and the sensitivity becomes clear.
Ask: Why did growth stocks fall more than value stocks when the Fed raised rates in 2022? The answer lies in where the earnings are. A value stock — say, a regional bank or a mature industrial company — earns most of its money in the near term. A growth stock earns most of its money in years 5, 8, 12. The farther out the cash flows, the harder a higher discount rate hits them. This is not intuitive, and it trips up experienced investors.
Cover buybacks and dilution together. Ask the student: if a company has 100 million shares and earns $500 million, that's $5 per share. If the company buys back 10 million shares, now 90 million shares earn $500 million — that's $5.56 per share. No change in the business, 11% increase in earnings per share. This is why large, profitable companies with limited reinvestment opportunities often buy back stock rather than pay dividends or sit on cash.
Close with the core principle: stock prices are forecasts, not scorecards. When you buy a stock, you are not grading the company's history. You are making a bet that the market's current forecast about the company's future is wrong, and that you know something or see something the consensus has not yet priced in. That is a hard thing to do consistently, and humility about your ability to do it is appropriate.
Pattern to Notice
Over the next two weeks, find at least one company that reports earnings and watch what happens to the stock price. Look up the analyst consensus estimate before the report and compare it to what the company actually reported. Notice whether the price moved in the direction you would have predicted from the results alone, or in the direction predicted by the beat/miss relative to expectations.
A Good Response
A student who has mastered this lesson can explain why a company with record profits might see its stock fall, can articulate what the discount rate is and why it matters more for growth stocks than value stocks, and can describe the expectation mechanism without prompting.
Moral Thread
Humility
The hardest part of investing is accepting that your read on a company's quality is not the same as your read on its price. A business can be excellent and its stock can still fall — because price reflects expectations, not just reality. Humility means holding those two things separately and resisting the urge to believe that being right about the business makes you right about the trade.
Misuse Warning
Do not conclude that fundamental analysis is useless because prices are driven by expectations. Expectations are ultimately anchored to fundamentals — a company that consistently beats expectations tends to see its stock rise over time. The lesson is that timing trades around earnings events is harder than it looks, not that understanding businesses is irrelevant.
For Discussion
- 1.A company reports earnings per share of $1.85 when consensus was $1.90. The stock falls 6%. A different company reports EPS of $0.40 when consensus was $0.55. Should the second stock fall more or less than the first? What factors would you consider?
- 2.Meta lost roughly $230 billion in market cap overnight on a guidance miss. What does that number represent, and who specifically lost that money?
- 3.If the Federal Reserve cuts interest rates significantly, which types of stocks would you expect to benefit most and why?
- 4.A company announces a $5 billion share buyback. The stock jumps 4% on the news. No earnings information was released. What does this tell you about how markets value capital allocation decisions?
- 5.Why might a management team intentionally set guidance below what they expect to deliver? What are the strategic advantages of 'sandbagging' estimates?
- 6.If you believed a company would report strong earnings, why might buying the stock right before the earnings report still be a bad strategy?
- 7.Explain the statement: 'Stocks are the present value of future cash flows.' What assumptions are embedded in that statement, and what can change those assumptions?
Practice
Earnings Expectation Autopsy
- 1.Choose a company that has reported earnings in the last 90 days. Find the analyst consensus estimate for EPS and revenue from a financial site before looking at the actual results.
- 2.Record the actual reported EPS and revenue, the consensus estimates, and the percentage by which the company beat or missed on each metric.
- 3.Find the stock's price change on the day after earnings were announced. Record the percentage move.
- 4.Write a paragraph explaining whether the price move matched the beat or miss, and identify any other factors — guidance, macro news, broader market movement — that may have contributed to the price change beyond the earnings results themselves.
Memory Questions
- 1.What does 'priced in' mean, and why does it matter for predicting stock price movements?
- 2.Meta's stock fell 26% on strong earnings. What was the actual cause of the decline?
- 3.Why do rising interest rates tend to hurt growth stocks more than value stocks?
- 4.What is guidance, and why can a guidance miss be more important than the current quarter's results?
- 5.How does a share buyback increase earnings per share even if the company's total earnings are unchanged?
- 6.In one sentence, what is a stock price?
A Note for Parents
This lesson can be made viscerally real by watching a single earnings release in real time together. Many companies report after market close at 4 p.m. Eastern; you can watch the after-hours price move alongside reading the press release. The key teaching moment is getting the student to state a prediction before looking at the stock's reaction — forcing them to use their own reasoning, then confronting the result. The goal is discomfort with overconfidence, not paralysis.
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