Why Do Stock Markets Rise and Fall? The Five Forces Behind Prices

Force 3: Interest rates, the price of time

A stock’s value is the sum of its future cash flows, discounted at a rate that starts from government bond yields. When yields rise, the same future profits are worth less today. Mechanically. The longer the profits sit in the future (typical of growth and tech stocks), the harder the repricing.

2022 is the reference case. The Fed raised its policy rate by 525 basis points between March 2022 and July 2023, and the S&P 500 fell 19% in 2022 while corporate earnings held near their record levels: the decline was a compression of valuation multiples, not a collapse of profits. Long-term bonds lost 31% the same year (ICE BofA indices), the direct bond-market translation of the same mechanism, detailed in why bond prices fall when yields rise. How rate decisions then reach the rest of the economy is traced in the transmission of interest rates to the real economy.

Force 4: Inflation, the constraint

Inflation acts on markets through two channels at once. It squeezes corporate margins wherever companies cannot pass costs on to customers. And above all, it forces the central bank’s hand: persistent inflation means higher policy rates, which activates Force 3.

When US consumer prices peaked at 9.1% year over year in June 2022 (BLS), the damage to equities did not come primarily from the inflation itself. It came from the 525 basis points of tightening it triggered. That indirect channel, inflation as the force that sets the price of money, matters more for a portfolio than the price of groceries, a distinction developed in what inflation does to savings and investments.

Force 5: Psychology and leverage, the amplifier

The four forces above set the direction. Psychology and borrowed money set the speed. Investors imitate each other, a documented pattern of herd behavior in markets, and many positions are financed with debt. When prices fall, leveraged investors receive margin calls and are forced to sell, which pushes prices lower, which triggers more calls. Fear does the rest.

That amplification loop is how the S&P 500 lost 34% between February 19 and March 23, 2020, about a month of trading, before recovering its prior high within roughly six months. The economic shock was real. The speed of the move was mechanical.

How the five forces combine: regimes

The forces rarely act alone. Their configuration at a given moment is what Eco3min calls a macroeconomic regime, and the same investing rule performs differently across regimes: the S&P 500 delivered zero real return between 2000 and 2013 (Damodaran, NYU Stern), then one of its strongest runs from 2010 to 2021 under zero rates and abundant liquidity. The regime-by-strategy matrix of this hub documents this page by page.

Markets do not grade the present; they reprice the future. The practical question is therefore not “is the news good?” but “what regime are these prices assuming?”. Here is where the classification stands today, computed from public institutional data:

Frequently asked questions

What makes a stock price move from one day to the next?

The balance between buy and sell orders, itself driven by changes in expectations. A price does not measure a company’s health in real time: it reflects what buyers and sellers, at that moment, are willing to pay for its future profits. Most daily moves trace back to revised expectations about earnings, interest rates or liquidity, not to changes in the business itself. Worth reading alongside: our analysis “Equity Markets vs Real Economy”.

How often do markets fall by 10% or more?

Regularly. The S&P 500 has averaged about 1.1 corrections of 10% or more per year since 1928 (Ned Davis Research). Schwab counts 27 corrections since November 1974 (data Morningstar, April 2025), of which only 6 deepened into bear markets of 20% or more. Frequent, mostly contained: that is the historical pattern.

Do market declines signal a coming recession?

Historically, not reliably. Economist Paul Samuelson quipped in 1966 that the stock market had predicted nine of the last five recessions, and the record since supports the joke: the 1987 crash and the 2022 bear market were both followed by no US recession (NBER dating), while some recessions arrived without a prior crash. A market decline is information about expectations and financing conditions, not a recession forecast.

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