Stock prices move because the number of people wanting to buy a stock and the number wanting to sell it are almost never perfectly balanced. When more money flows toward buying, the price rises. When more flows toward selling, it falls. That simple tug-of-war plays out millions of times a day across thousands of stocks, driven by a mix of company news, economic data, and plain human emotion.
Prices Are Set by Buyers and Sellers
Every stock has two key prices at any given moment: the bid (the highest price a buyer is currently willing to pay) and the ask (the lowest price a seller is willing to accept). The gap between them is called the spread. When a flood of buyers shows up and relatively few sellers are offering shares, buyers have to raise their bids to attract sellers, and the price ticks upward. The reverse happens when sellers outnumber buyers: they have to lower their asking prices to find a match, and the stock drops.
Market makers, the firms that stand ready to buy and sell shares throughout the trading day, help keep this process orderly by executing trades on both sides. But even they adjust their prices based on the flow of orders. If limit orders to buy dry up and selling pressure builds, the spread widens and the price can fall quickly. Conversely, a surge of buy orders compresses the spread and pushes the price higher. This is why a stock can move several percent in seconds after a big news headline: thousands of traders are suddenly trying to get on the same side of the trade at once.
Company Earnings Drive Long-Term Value
Over months and years, the single biggest force on a stock’s price is how much money the company actually makes, and how much investors expect it to make in the future. Public companies report their revenue, profit, and spending every quarter. Alongside those numbers, many also issue guidance: a forecast of what they expect to earn in the coming quarter or year, including sales projections, anticipated spending, and sometimes details like inventory levels and cash flow.
What matters most is not whether the numbers are objectively “good” or “bad,” but how they compare to what the market already expected. If a company reports earnings above expectations and raises its guidance, analysts may upgrade the stock, attracting more buyers and pushing the price up. If management issues guidance below what Wall Street anticipated, analysts may downgrade the stock, prompting investors to sell. A company earning billions of dollars can still see its stock drop 10% in a day if those billions fell short of the consensus forecast by even a small margin.
Companies can also revise their guidance mid-quarter if conditions change, and those revisions move prices too. Under a rule called Regulation FD, companies must share this kind of information with all investors at the same time, so no one gets an early look. The result is that earnings season (the weeks when most companies report results) tends to produce some of the largest single-day moves in individual stocks.
Economic Data Moves the Whole Market
Individual stocks respond to company-specific news, but the broader market rises or falls in response to economic data that affects virtually every business. The two reports that consistently trigger the biggest reactions are the monthly jobs report (specifically non-farm payrolls) and the core Consumer Price Index, which measures inflation excluding volatile food and energy prices.
Research from NYU Stern found that a negative surprise of 100,000 jobs in the payroll report causes the VIX (a widely watched measure of expected market volatility) to jump by about 0.3 percentage points at market open. That may sound small, but it reflects a rapid repricing of risk across the entire S&P 500. Core CPI surprises are even more directly tied to stock prices: a one-percentage-point unexpected increase in monthly core CPI was associated with a move of over 22 points in the S&P 500 index.
The reason these two reports matter so much is that they influence what the Federal Reserve does with interest rates. Strong job growth or rising inflation suggests the Fed may keep rates higher for longer, which makes borrowing more expensive for companies and makes bonds relatively more attractive compared to stocks. Weak job numbers or falling inflation suggest rate cuts could be coming, which tends to boost stock prices. Other data points like GDP growth, retail sales, and housing starts get attention too, but studies show they don’t reliably move markets on their own the way jobs and inflation data do.
Interest Rates Change What Stocks Are Worth
When interest rates rise, two things happen that push stock prices down. First, companies that borrow money to fund their operations or growth face higher costs, which eats into profits. Second, safer investments like Treasury bonds and savings accounts start paying more attractive returns, so some investors shift money out of stocks and into those alternatives. When rates fall, the opposite dynamic plays out: borrowing gets cheaper, bonds pay less, and stocks look relatively more appealing.
This effect hits some stocks harder than others. Companies that carry a lot of debt, like utilities and real estate firms, are more sensitive to rate changes. So are fast-growing tech companies whose value depends heavily on profits expected years into the future. When rates rise, those distant future profits are worth less in today’s dollars, a concept investors call the discount rate. That is why growth stocks can drop sharply on days when the Fed signals it plans to keep rates elevated.
Emotions Push Prices Beyond Fundamentals
If stocks moved only on earnings and economic data, price swings would be modest and predictable. They are neither, because human psychology plays an enormous role. Fear and greed are the two dominant emotions in markets. When investors are greedy, they pile into stocks that are already rising, pushing prices above what the underlying business performance would justify. When fear takes hold, investors rush to sell, driving prices below what the companies are actually worth.
CNN’s Fear and Greed Index tries to quantify this by tracking seven indicators, including the balance between put options (bets that stocks will fall) and call options (bets that stocks will rise). When puts far outnumber calls, the market is fearful. When calls dominate, greed is in charge. The index operates on a simple premise: excessive fear drags share prices below their intrinsic value, and excessive greed inflates them beyond it.
The 24-hour news cycle amplifies these swings. A dramatic headline about a bank failure, a geopolitical crisis, or a trade war can trigger a wave of selling that has nothing to do with whether any individual company’s business actually changed. Investors react to the story first and reassess later. This is why markets sometimes plunge 3% on a Monday and recover most of it by Wednesday. The fundamentals did not change in 48 hours. The mood did.
How All These Forces Work Together
On any given day, a stock’s price reflects the combined weight of all these factors at once. A company might report strong earnings, but if the broader market is selling off because of a surprisingly hot inflation report, the stock could still fall. Or a company with mediocre results might rally because investors are in a risk-taking mood and the Fed just signaled a rate cut.
Over short periods (days to weeks), sentiment and macroeconomic surprises tend to dominate. Stocks move in ways that can feel random because traders are reacting to headlines, adjusting for new data, and following momentum. Over longer periods (years to decades), company fundamentals win out. A business that consistently grows revenue and profit will see its stock price rise over time, regardless of how many scary headlines appeared along the way. A business that steadily loses money will see its stock decline no matter how much hype surrounds it.
Understanding this distinction is practical. Short-term price drops often reflect temporary shifts in mood or macroeconomic noise rather than permanent damage to a company’s value. Long-term price trends, on the other hand, almost always track the financial performance of the underlying business.