What is a Trough?

A trough is the stage of the economy's business cycle that marks the end of a period of declining business activity and the transition to expansion. The business cycle is the upward and downward movement of gross domestic product and consists of recessions and expansions that end in peaks and troughs.

Trough are important as they mark a positive turning point for the economy.

phases of the business cycle
 Investopedia

Technical traders also sometimes refer to swing lows as troughs, and swing highs as peaks. Asset prices move up and down, forming peaks and troughs.

Key Takeaways

  • The business cycle is composed of troughs, expansions, peaks, and contractions.
  • A trough is a bottoming process where contraction ends and expansion begins.
  • The actual trough is typically only visible in hindsight, once the economic indicators begin to show improvement. Until that time, it is possible the economy is still in contraction.
  • A trough is marked by conditions like higher unemployment, layoffs, declining business sales and earnings, and lower credit availability.

Understanding an Economic Trough

The business cycle moves in four phases: trough, expansion, peak, and contraction. The trough is the bottoming process of moving from contraction, or declining business activity, to expansion which is increasing business activity.

Economists use several metrics to track the economic cycle throughout its various phases. The most recognizable of these is gross domestic product (GDP), which is the total value of all goods and services that a country produces.

Employment levels also offer an indicator of where the economy stands in the business cycle. Unemployment levels of less than five percent are consistent with full employment and are indicative of economic expansion. When the unemployment rate rises from month to month, the economy has most likely entered a contractionary phase. When the unemployment rate bottoms out, a trough has likely occurred.

Incomes and wages are also indicators for where the economy stands in the business cycle. These increase during expansion, recede during contraction, and bottom out during a trough.

The major U.S. stock market indices, such as the Dow Jones Industrial Average (DJIA) and Standard & Poor's (S&P) 500 Index also track closely with the business cycle. Declines in the stock market coincide or foreshadow contraction in the economy. When stocks rally after a significant decline it could signal the economic trough is in or coming soon, leading to a rise in economic activity.

Troughs are recognizable in hindsight, but harder to spot in real-time. As the economic indicators contract, the economy is in a contraction phase. This phase can last for a short or long period of time. It is only once the economic activity begins to increase again, as shown on economic indicators, that expansion is likely underway and the trough (or bottom) has been put in.

While troughs vary in severity—with some troughs only being minor setbacks in economic growth, and others being sustained periods of hardship—they are typically marked with declining business sales and earnings, layoffs, low credit availability, higher unemployment, and business closures (all compared to the other business cycle phases).

Examples of Economic Troughs in the US

An economic trough occurred in June 2009. This date marked the official end of the Great Recession, which began following the economic peak reached in December 2007. At the end of 2007, the U.S. GDP reached an all-time high of $14.99 trillion. It then fell steadily for the next year and a half, a period of strong economic contraction. In June 2009, it bottomed out at $14.36 trillion. A period of expansion ensued, with the GDP eventually surpassing its 2007 high, reaching $15.02 trillion by September 2011.

US GDP over time
US GDP Over Time.  Federal Reserve Bank of St. Louis

During the U.S. recession of the early 1990s, the trough occurred in March 1991. At that date, the GDP stood at $8.87, down from $8.98 trillion in July 1990, the month the recession began. The recovery to this recession, marked by the ensuing expansionary phase, was robust, with the GDP surpassing $9 trillion for the first time ever before the end of 1991.