More than 5,700 companies are listed on the New York Stock Exchange and the Nasdaq Stock Exchange, the two largest trading platforms for U.S. securities. Some of those companies are grouped into indexes that measure different aspects of the domestic stock market. Certain indexes are quite broad, while others are rather niche.

The three most popular U.S. stock indexes are in the black this year. The broad-based S&P 500 (^GSPC -0.41%) has advanced 15%, the blue-chip Dow Jones Industrial Average (^DJI -0.12%) has advanced 4%, and the growth-focused Nasdaq Composite (^IXIC -0.71%) has advanced 19%.

Read on to learn how all three stock market indexes performed over the past 15 years.

The S&P 500: 15-year return of 495% (12.6% annually)

The S&P 500 tracks 500 large and profitable U.S. companies. The index is weighed by market capitalization, such that larger companies have more influence over its performance. It includes value stocks and growth stocks from all 11 market sectors, and it covers about 80% of U.S. stocks by market capitalization.

The S&P 500 is generally considered the best benchmark for the entire U.S. stock market due to its scope and diversity. Investors can get exposure to the index through the Vanguard S&P 500 ETF (VOO -0.39%). The five largest positions in the index fund are listed by weight below.

  1. Microsoft: 6.9%
  2. Apple: 6.3%
  3. Nvidia: 6.1%
  4. Alphabet: 4.2%
  5. Amazon: 3.6%

The S&P 500 returned 495% over the last 15 years, which is equivalent to 12.6% annually. At that pace, $50 invested weekly in the Vanguard S&P 500 ETF would be worth $101,000 in 15 years and $705,000 in 30 years.

Dow Jones Industrial Average: 15-year return of 362% (10.7% annually)

The Dow Jones Industrial Average tracks 30 U.S. companies. The index is weighted by share price, such that companies with more expensive stocks have more influence over its performance. It is not governed by strict inclusion criteria, but the selection committee focuses on companies with a good reputation, a history of sustained growth, and broad interest among investors.

The Dow Jones Industrial Average is generally considered a barometer for blue-chip stocks. Investors can get exposure to the index through the SPDR Dow Jones Industrial Average ETF (DIA -0.11%). The five largest positions in the index fund are listed by weight below.

  1. UnitedHealth Group: 8.1%
  2. Goldman Sachs Group: 7.8%
  3. Microsoft: 7.6%
  4. Home Depot: 5.7%
  5. Caterpillar: 5.5%

The Dow Jones Industrial Average returned 362% over the last 15 years, which is equivalent to 10.7% annually. At that pace, $50 invested weekly in the SPDR Dow Jones Industrial Average ETF would be worth $87,000 in 15 years and $488,000 in 30 years.

Nasdaq Composite: 15-year return of 873% (16.4% annually)

The Nasdaq Composite tracks more than 3,000 companies, the vast majority of which are domestic companies. The index is weighted by market capitalization, such that more valuable companies have more impact on its performance. Only stocks listed exclusively on the Nasdaq Stock Exchange are included.

The Nasdaq Composite is widely seen as a benchmark for growth stocks, especially those in the technology sector. Investors can get exposure to the index by purchasing shares of the Fidelity Nasdaq Composite ETF (ONEQ -0.67%). The five largest positions in the index fund are listed by weight below.

  1. Microsoft: 11.4%
  2. Apple: 10.9%
  3. Nvidia: 10.1%
  4. Alphabet: 7.4%
  5. Amazon: 6.8%

The Nasdaq Composite returned 873% during the last 15 years, which is equivalent to 16.4% annually. At that pace $50 invested weekly in the Fidelity Nasdaq Composite ETF would be worth $137,000 in 15 years and $1.4 million in 30 years.

Regular investments and patience are the keys to stock market success

The U.S. stock market performed well over the last 15 years. But investors should not expect identical returns in the future. Returns fluctuate based on the economic environment. For instance, the U.S. economy was recovering from the Great Recession 15 years ago, so domestic stocks were primed to soar. But the U.S. economy was headed toward the Great Recession 20 years, so the domestic market was primed to decline.

The chart below shows how the three major U.S. stock indexes performed over different time periods. Importantly, performance is measured by price returns, meaning dividend payments were excluded. Notice that all three stock indexes achieved lower annual returns over the last 20 years as compared to the last 15 years.

A chart showing the annualized returns in the three major U.S. stock market indexes over different time periods.

The three major U.S. stock indexes have generally delivered robust returns in the past, but their performance has fluctuated over different time periods due to variations in the economic climate.

Dividend payments contribute heavily to the performance of all three major stock indexes. For example, had dividends been reinvested over the last 20 years, the S&P 500 would have returned 10.3% annually, the Dow Jones Industrial Average would have returned 9.2% annually, and the Nasdaq Composite would have returned 12.5% annually.

Going forward, the U.S. stock market will continue to create wealth for patient investors, but its performance will fluctuate based on transient macroeconomic factors like inflation and interest rates. Investors can compensate for those fluctuations by consistently adding money to any index funds that track the S&P 500, Dow Jones Industrial Average, or Nasdaq Composite. In other words, avoid strategies that depend on market timing.