Every Trade Has a Buyer and Seller—So Why Does Price Move?

Every trade has both a buyer and a seller—so why does the price move? This visual lesson builds a tiny order book from scratch and shows exactly how aggressive orders, limit orders, cancellations, liquidity, and changing expectations become the prices you see on a chart. You’ll learn: • the difference between bid, ask, and last price • how one order can execute at several prices • why a quote can move without any trade • how news becomes orders rather than moving price by itself • why the same order can have a different impact in a thin market CHAPTERS 0:00 The buyer–seller paradox 1:06 Bid, ask, and last 2:04 Build a tiny market 3:11 The 180-share order 5:04 A quote moves without a trade 6:05 How news becomes orders 6:58 Why liquidity matters 7:39 What the model leaves out 8:27 Five quick questions 9:47 The mechanism checklist Primary references include Investor.gov, Nasdaq, the SEC, the Federal Reserve, the New York Fed, NYSE, and published market-microstructure research. This video is educational and does not provide investment advice. Market structures differ across assets and venues.