The Standard & Poor's 500 stock index returned an average annual return of 17.3 percent in the 1980s before adjusting for inflation and an average real total return of 11.6 percent after adjusting for inflation, according to data provided by Simple Stock Investing. Stocks tracked by the index appreciated by an average of 12.6 percent a year and paid an average of 4.6 percent each year in dividend distributions.
In absolute terms, the S&P 500 index opened at 107.94 on the first day of trading in January 1980, according to data provided by Yahoo Finance, and closed the decade at 353.40 on the final day of trading in December 1989. This represented a much stronger performance than the S&P 500 achieved in the 1970s, when the index only managed to increase from 92.06 to 107.94 during the entire decade. The S&P 500 gained value in every year of the 1980s except for 1981.
The U.S. economy experienced recessions between January and July 1980 and again from July 1981 until November 1982, according to Advisor Perspectives, but the S&P 500 gained value during each of those recessions. Later, on October 19, 1987, the S&P 500 suffered its worst single-day collapse ever, according to Market Watch. The S&P 500 opened that day at 282.70 and closed at 224.84, according to Yahoo Finance data, representing a single-day loss of 20.5 percent. However, the index still showed an overall gain for the year 1987.