JPMorgan Chase has flourished since Jamie Dimon became CEO in 2006. The company survived the financial crisis of 2008 and has gone on to become the largest bank in the world by market capitalization. Not surprisingly, Dimon has earned a reputation as a fount of financial wisdom, which makes his recent warning all the more concerning.

Earlier this month, Dimon told CNBC that serious economic headwinds -- high inflation, rising interest rates, and Russia's war in Ukraine -- would probably "put the U.S. in some kind of recession six to nine months from now." He also noted the global economy would likely suffer the same fate.

Those concerns have already hit the stock market hard. The S&P 500 delivered its worst first half since 1970 this year, and the broad-based index is currently about 20% off its high.

Dimon's comments may have investors even more rattled than before, but here are two smart index funds to buy and hold through any economic downturn.

Vanguard S&P 500 ETF: A good option for risk-tolerant investors

The Vanguard S&P 500 ETF (VOO -0.07%) tracks the performance of the S&P 500, which itself comprises about 500 of the largest U.S. companies. The Vanguard ETF represents a blend of value stocks and growth stocks that span all 11 market sectors, though certain sectors are weighted more heavily, meaning they have a greater impact on the ETF's performance.

Here are the top five sectors by weight:

  • Information Technology: 26.4%
  • Health Care: 15.1%
  • Consumer Discretionary: 11.7%
  • Financials: 10.9%
  • Consumer Staples: 8.1%

Here are the top five holdings by weight:

  • Apple: 6.9%
  • Microsoft: 5.7%
  • Alphabet: 3.6%
  • Amazon: 3.3%
  • Tesla: 2.3%

Over the past decade, the Vanguard S&P 500 ETF generated a total return of 226%, or 12.5% per year. At that pace, $400 invested on a monthly basis would be worth $92,000 in a decade, and it would be worth almost $1.4 million in three decades.

The Vanguard S&P 500 ETF is a particularly attractive investment option right now for a few reasons: First, it allows investors to build a diversified portfolio of large-cap stocks without doing much work. Second, the benchmark (i.e. the S&P 500) has weathered many bear markets and recessions in the past, and it has always recovered. Third, the rolling 20-year return of the S&P 500 has been positive for the last 103 periods, according to Crestmont Research. That means investors can sleep soundly knowing a positive return is all but guaranteed with a long enough holding period.

Here's the big picture: The S&P 500 could fall much farther in the coming months, especially if the U.S. economy does indeed wind up in a recession. But historical data suggest bear markets are an excellent time to buy stocks. Additionally, the Vanguard S&P 500 ETF bears an expense ratio of just 0.03%, meaning the annual fee is just $3 on a $10,000 portfolio. That makes the ETF a good option for risk-tolerant investors.

Vanguard S&P 500 Value ETF: A good option for risk-averse investors

The Vanguard S&P 500 Value ETF (VOOV -0.05%) tracks the performance of value stocks in the S&P 500, as measured by three factors: price-to-book ratio, price-to-sales ratio, and price-to-earnings ratio. This Vanguard ETF includes 449 stocks that span all 11 market sectors.

Here are the top five sectors by weight:

  • Health Care: 17.8%
  • Financials: 14.9%
  • Industrials: 12%
  • Consumer Staples: 11.6%
  • Information Technology: 10.9%

Here are the top five holdings by weight:

  • Berkshire Hathaway: 3.1%
  • Johnson & Johnson: 2.8%
  • ExxonMobil: 2.3%
  • Procter & Gamble: 1.9%
  • UnitedHealth Group: 1.8%

Due to its composition, the Vanguard S&P 500 Value ETF tends to be slightly less volatile than the broad market, as evidenced by its three-year beta of 0.89. In other words, the Vanguard ETF tends to fall less dramatically (and rise less dramatically) than the S&P 500. For example, the Vanguard ETF is currently 11% off its high, but the S&P 500 has dropped almost 20%.

Of course, lower risk also means lower reward. The Vanguard S&P 500 Value ETF generated a total return of 168% over the last decade, underperforming the S&P 500 by a wide margin.

Here's the big picture: In the event of a recession, the Vanguard S&P 500 Value ETF may be more stable than the broader S&P 500, simply because value stocks tend to be less volatile than growth stocks. That makes the Vanguard S&P 500 Value ETF a good option for risk-averse investors that still want exposure to the U.S. stock market. Additionally, the Vanguard ETF bears a relatively low expense ratio of 0.1%, meaning the fee is just $10 per year on a $10,000 portfolio.