One ETF that’s shown strong growth is iShares MSCI USA Momentum Factor ETF (NYSEMKT: MTUM). The fund invests in large and midsize companies that show price momentum. Larger holdings in the portfolio include Tesla, Apple, Amazon, NVIDIA, Adobe, and Google.

In the 12 months prior to October 31, 2020, the fund produced a total return of 19.72%. In the same time period, the S&P 500 grew 9.71%. MTUM pays a quarterly dividend, but the yield is less than 1%.

Saving for college would be far easier if you could count on those 20% returns indefinitely, but that’s just not realistic. You can see that from the fund’s three-year returns, which are closer to 13%. Plus, it’s likely that this fund could underperform the S&P 500 in down markets, which would reduce that growth rate over longer periods of time. A more appropriate growth rate for planning purposes would be 10%, which is still aggressive but not impossible.

Assuming your combined federal and state tax rate is 25%, you’d have to invest $2,900 annually to reach $86,891 after 15 years. That’s probably the minimum amount you’d want to save, considering that the projected $87,000 is for tuition only — meaning no room and board or other college-related costs. So you’ll need more than $87,000 if you want the option for your kid to live in the dorms or attend a private school, instead.