What Makes a Stock Go Up or Down?

- By Mitchell Mauer

When it comes to the stock market, one thing is for certain: stocks go up and stocks go down. The question is, what makes a stock go up or down?

What makes a stock go up or down is determined by the recent operating results of a business and its future expectations.

This means stock prices reflect both fundamentals (operating results) and emotions (future expectations). When either one or both of these change for a particular stock, its price will be affected.

What makes a stock go up (or down)?


It’s impossible to pinpoint exactly what makes a stock go up or down on a daily basis. To borrow a phrase from The Princess Bride, “Anyone who says differently is selling something.”

On the other hand, it’s quite simple to see what makes a stock go up or down over time. Stock prices are based on how investors think a company will perform in the future compared to how the company is performing now.

In any investment, investors are betting on the future. Because the future is uncertain, stocks cannot be priced based on a business’s current operating results alone. They must be valued by predicting future performance.

Price ratios

In order to quantify these predictions, investors use price ratios. Price ratios are simple tools that show how a stock is priced compared to its recent operating results.

For example, a Price-to-Earnings (P/E) ratio of –…, says that a stock is valued –… times higher than its current earnings.

This does not mean that investors expect the company’s earning to increase by a multiple of –… in the near future. It merely means that if the earnings were to stay constant, investors would break even on their initial investment after –… years. In other words, the earnings yield on the principle is –…% (–…/–…… = ….–).

Say a stock has a P/E of 5… and investors still expect to receive an earnings yield of –…%. Paying 5… times earnings only makes sense if the company’s earnings are expected to increase substantially over time.

Multiple futures

No matter how badly stock analysts pretend to be fortune tellers, no one can accurately forecast a company’s future performance (especially on a consistent basis).

Charles Duhigg, in his book "Smarter, Faster, Better: The Secrets of Being Productive in Life and Business," summarizes the reality of what the future is. Duhigg says, “The future isn’t one thing. Rather, it is a multitude of possibilities that often contradict one another until one of them comes true.”