Every single 20-year period in S&P 500 history has produced positive returns. Every time.
Over every 20-year rolling period in the history of the S&P 500 — including periods that contained the Great Depression, World War II, the 1970s stagflation, the dot-com crash, the 2008 financial crisis, and COVID — investors who held for 20 years made money. Every time.
Your child's account cannot be touched for 18 years. By the time they have any choice about what to do with it, the most dangerous window for investment risk will already be closed.
What risk actually means
When most people hear that investing is risky, they imagine losing everything. That is not what investment risk means in practice.
Risk in investing is the possibility that the value of your investment will be lower at some point in the future than it is today. The critical word is at some point. A portfolio that drops 30% in a crash has not lost 30% permanently. It has lost 30% on paper, on that day, if you sold everything that day.
The investor who sold in March 2020 when the market dropped 34% in five weeks locked in a real loss. The investor who did nothing watched the market recover fully within six months and reach new highs within a year. These are two completely different outcomes, and the only variable was whether they sold.
The relationship between risk and time
Investment risk and time are inversely related. The longer your time horizon, the lower your real risk. Here is what the historical data shows consistently:
What volatility actually looks like
Between 1980 and today, the S&P 500 has averaged a drop of roughly 14% at some point during each calendar year. That includes the years it finished up 20% or more.
In other words, volatility is not a sign that something is wrong. It is the normal texture of the market in any given year. The investors who panic during those drops and sell are not responding to a real threat, but a feeling of anxiety and dread.
Your child's account has a structure that makes this easier to handle than most investments. The money cannot be withdrawn before 18 regardless of what the market does. There is no button to press in a panic. The account simply continues compounding through every crash, every recovery, and every new high.
The real risks
Given all of this, the question worth asking is not whether the stock market is risky. It is what the actual risks to your child's account are.
There are two.
The first is withdrawing at 18. An account that gets cashed out the moment it unlocks captures 18 years of compounding and nothing more. The account that stays invested captures 47 more years on top of that. That decision, made once at 18, is worth more to your child's financial life than almost anything else they will ever do with money.
The second is not contributing. An account that sits at the seed balance and never receives additional contributions still roughly triples in size by 18. But an account that receives consistent contributions becomes something else entirely. The difference between contributing nothing and contributing $100 a month over 18 years is not $21,600. It is over a million dollars by age 65.
Risk is real. Markets crash, and some years are genuinely terrible. None of that changes the underlying case for a long-term investment in a diversified index fund held for decades.
The parents who understand this will not panic when the market drops during their child's youth. They will not make fearful decisions about an account that is not designed to be touched anyway. And when their child turns 18 and asks what to do, they will have an answer grounded in 100 years of data rather than whatever the market happened to do last week.