Fund Performance The fund has returned 10.10 percent over the past year, 10.32 percent over the past three years, 10.97 percent over the past five years and 11.14 percent over the past decade.

Investing in Vanguard's VOO is a low-stress way for investors to access the U.S. equity market; however, there is the risk of loss as with any investment, and investors should consult a financial professional before investing in the Vanguard S&P 500 ETF.

It also comes with a respectable 1.35% annualized yield, a figure on par with most broadly diversified ETFs. Among its 3,717 stock holdings, Microsoft (MSFT 0.13%), its largest position, accounts for 6.12% of the fund's portfolio. VTI has averaged an annual return on investment of 12.3% over the past five years.

How much does it cost to buy Vanguard index fund shares? Investors make an initial minimum investment — typically around $3,000 — and pay annual costs to maintain the fund, known as an expense ratio, based on a small percentage of your cash invested in the fund.

The S&P 500 more than doubled the performance of the Russell 2000 over the last decade, so I would encourage passive investors to prioritize an S&P 500 index fund. But given the current market environment, allocating 5% to 15% of a portfolio to the Vanguard Russell 2000 ETF is a sensible move.