Introduction to Stocks — What Moves Individual Share Prices

Indices give you the broad picture, how the market as a whole is performing. But within every index are hundreds of individual companies, each with its own story, its own drivers, and its own price movements that often have nothing to do with what the rest of the market is doing.

Apple can fall 8% on the same day the S&P 500 rises 1%. Tesla can rise 15% in a single session while the NASDAQ 100 barely moves. A pharmaceutical company can double overnight when it announces a successful drug trial. An airline can lose a third of its value in a day when it warns that fuel costs are destroying its margins.

Individual stocks are louder, faster, and more unpredictable than indices. They offer larger moves and therefore larger potential profits. They also carry risks that indices simply do not, the risk of a single piece of bad news wiping out weeks of gains in minutes.

A share price is ultimately an expression of what investors collectively believe a company is worth. And what a company is worth depends on how much profit it is expected to generate in the future.

The market is constantly asking one question about every company at every moment. How much money will this business make over the next five, ten, twenty years? And what is that future stream of profits worth in today''s terms?

Everything that moves a share price is, at its root, changing the answer to that question. New information arrives. Investors update their estimates of future profits. They buy if the new estimate is higher. They sell if it is lower. The price moves.

Four times a year, every publicly listed company releases a detailed financial report showing its revenues, costs, profits, and cash flows for the previous three months. This report also typically includes guidance, management''s forecast for the next quarter and sometimes the full year.

The market reaction to an earnings report is almost never about the absolute level of profits. It is about the surprise relative to what analysts expected.

A technology company reports earnings per share of $2.50. Analysts expected $2.20. The company beat expectations by $0.30. The stock rises 10%. Not because $2.50 is a great number in isolation but because it is better than the $2.20 that was already priced in.

Now flip it. The same company reports $2.50 earnings per share but analysts expected $2.80. The stock falls 12%. The company still earned $2.50 per share, a strong result by any measure, but it disappointed against expectations.

This dynamic, the importance of the surprise rather than the absolute number, is the most important thing to understand about how earnings move share prices. And guidance matters even more than the historical number. A company that beats earnings but cuts its outlook for next quarter will almost always fall sharply, regardless of how good the current numbers look.

Product launches change expectations about future revenue. When Apple announces a new iPhone, the market immediately begins estimating how many units it will sell and what that means for earnings. A product that exceeds expectations drives the stock higher. A product that disappoints drives it lower.

Management changes matter enormously. The announcement that a company''s CEO is stepping down, particularly unexpectedly, can cause a significant share price reaction in either direction depending on whether the market considered the outgoing CEO an asset or a liability.

Legal and regulatory events can be devastating. A pharmaceutical company that loses a patent lawsuit on its key drug, an oil company facing massive fines for an environmental disaster, a technology company that loses an antitrust case. All of these can cause sudden and severe share price declines.

Mergers and acquisitions create some of the most dramatic single-day moves in individual stocks. When a company announces it is being acquired, its share price typically jumps to near the acquisition price almost immediately, sometimes 30 to 50% in a single day.

Rising interest rates are bad for homebuilder stocks. Higher mortgage rates mean fewer people can afford homes and construction slows. They are bad for utility companies, whose steady dividend yields become less attractive relative to safer fixed-income alternatives. They are good for bank stocks, which earn more on the loans they make as rates rise.

A strong dollar is bad for US multinationals. It reduces the dollar value of revenues earned overseas. It is good for domestic US companies whose revenues and costs are both in dollars.

Falling oil prices are bad for energy company stocks and good for airlines. Fuel is one of the largest costs for carriers and cheaper fuel directly boosts profitability.

Understanding these macro sensitivities, knowing which direction the wind is blowing for a given company''s sector based on the current economic environment, is what allows you to be selective about which stocks to trade and in which direction.