Supply and demand — but what drives demand?
The textbook answer is correct: when more people want to buy a stock than sell it, the price rises; when more want to sell, it falls. That is supply and demand.
But that just pushes the question back. What makes people want to buy or sell in the first place? Use the simulator to see how the balance of buyers and sellers sets the price directly.
Supply & demand simulator
Shift the balance and watch how price responds.
Buyers
50
want to buy
Price
$100.00
Sellers
50
want to sell
Relatively balanced. Buyers and sellers broadly agree on fair value. Small fluctuations happen, but no strong directional pressure either way.
Markets price the future, not the past
This is the most counterintuitive thing about stocks — and once you understand it, you will never be confused by financial news again. Stock prices are not a report card for what happened; they are a collective bet on what is going to happen.
That is why a company can report record profits and still fall 15%. If investors expected even bigger profits, the record results are a disappointment relative to expectations. Click each scenario to see how the same event produces opposite reactions.
The expectations game
Same event, different outcomes — depending on what was expected before it happened. Click a card.
Bull markets, bear markets, and everything between
Individual stocks move for company-specific reasons, but the whole market moves together too — driven by the economy, interest rates and collective psychology. These broader phases have names. Click each one to understand what it means.
Market phases — a stylized index over time
Bull market
A sustained period of rising prices — typically 20%+ gains over months or years.
- Driven by strong economic growth, low unemployment and rising corporate earnings
- Investor confidence is high — people are eager to buy
- Can last years: the 2009–2020 US bull market ran 11 years
- Risk: late-stage bulls often breed complacency and overvaluation
Fear and greed — the two forces that override logic
Rational analysis explains a lot of price movement, but not all of it. Two very human emotions — fear and greed — regularly push prices far beyond what any fundamental analysis would justify. Understanding them protects you from your own worst instincts.
Fear & Greed meter
Move the slider to explore how sentiment shifts investor behavior.
Neutral
The market is fairly priced relative to recent history — neither stretched up nor beaten down.
When fear dominates
Investors sell even good companies. Prices fall below fundamental value, and long-term buyers see opportunity. Warren Buffett: "Be greedy when others are fearful."
When greed dominates
Investors buy anything that is going up. Prices detach from reality and bubbles form — the dot-com crash, 2008 housing and crypto in 2021 all followed extreme greed.
Why someone would bet against a stock
Everything so far has been about buying because you think a price will go up. But some investors do the opposite — they profit when a stock falls. This is called short selling, and it explains why bad news sometimes causes a drop that seems too fast to be real.
You borrow 10 shares from someone who owns them
A broker facilitates this. The original owner still "owns" them on paper, but you temporarily hold them — and pay a borrowing fee for the privilege.You sell those 10 shares immediately at today’s price ($50 each = $500)
You now hold $500 cash but owe 10 shares back to the lender. You are betting the price falls before you have to return them.Price falls to $30. You buy 10 shares back for $300.
You return the 10 shares as promised. Your profit: $500 − $300 = $200 (minus fees). You made money as the stock fell.The risk: if the price rises, your losses are unlimited
If the stock goes from $50 to $200, you still have to buy 10 shares back to return them — now for $2,000. The $500 you received from the sale isn’t yours to keep — you owe the shares back — so it won’t cover the buy-back, and there’s no ceiling on how high the price (and your loss) can go. This is why short selling is dangerous, and why short squeezes (like GameStop in 2021) can be so violent.
Check your understanding
A major retailer announces it hired 10,000 new employees and is opening 200 new stores next year. Despite this positive-sounding news, the stock falls 8%. What is the most likely reason?
During the 2020 Crash, the S&P 500 fell 34% in 33 days — the fastest bear market in history — then fully recovered in 5 months. What best explains this speed in both directions?
What does "the market is forward-looking" mean in practice?
Now play: Chart Challenge
Can you identify the market phase from a price chart alone? You will be surprised how quickly the patterns start to click.
Next up: stocks vs bonds vs ETFs vs crypto — how to tell the major asset classes apart.