There's a piece of arithmetic that every investor should be required to learn before they're allowed to open a brokerage account. It's not complicated. It doesn't require a finance degree. It's simply this: the market's return is the sum of all investors' returns, before costs. After costs, the average investor must underperform the market by the amount of those costs. This is not a theory. It's not a debatable proposition. It is a mathematical identity, as certain as two plus two equals four. And yet, the entire financial industry is built on the premise that this arithmetic can be defeated.
Let me break it down more concretely. The stock market, in aggregate, is owned by all the investors in the world. Some of those investors are active — they try to pick winning stocks and avoid losing ones. Some are passive — they simply buy the entire market and hold it. The returns of the market are simply the weighted average of all these investors' returns. Before fees, the average active investor earns exactly the market return, because together they are the market. After fees — management fees, trading costs, taxes from turnover — the average active investor must underperform the market. There is no escape from this logic. For every active manager who beats the market, another must underperform by an equal amount.
The data bears this out with brutal consistency. Over the past fifteen years, roughly 85% to 90% of actively managed U.S. stock funds have underperformed their benchmarks. The numbers are even worse over longer periods. Over twenty-year horizons, the underperformance rate approaches 95%. These are not marginal failures. The average active fund underperforms by roughly the amount of its fees — typically 1% to 2% per year. Compounded over decades, that gap is enormous. A $100,000 investment earning 8% annually grows to about $466,000 after twenty years. At 6.5% — just 1.5% less — it grows to only $352,000. That's $114,000 that disappeared into fees, taxes, and trading costs. That's real money, and it's being transferred from investors to the financial industry every single day.
Given this evidence, you might wonder why anyone still invests in active funds. The answer is marketing. The industry spends billions of dollars convincing people that past performance predicts future results, that star managers exist, and that complex strategies can generate alpha. They don't lie outright — they simply show you the funds that happened to beat the market over the past five years, conveniently ignoring the hundreds of funds that were closed or merged after underperforming. This is called survivorship bias, and it makes active management look far better than it actually is.
There's another, deeper reason people are drawn to active management: it feels like it should work. The world is full of experts — doctors, lawyers, engineers — who add value through their specialized knowledge. It's natural to assume the same is true in investing. But investing is not like medicine or law. It's a zero-sum game relative to the market, and the competition is not other amateurs. It's institutions with supercomputers, PhDs, and access to information that you and I can only dream of. When you buy a stock, someone else is selling it. That someone is probably a professional who knows more than you do. Betting against them is not a strategy. It's a donation.
The beauty of low-cost index investing is that it bypasses this entire game. Instead of trying to beat the market, you simply accept the market's return, minus a tiny fee — often less than 0.05% annually. You won't outperform in any given year. But over decades, you will outperform the vast majority of professionals who are trying to do exactly that. The simplicity of this approach is its greatest strength. You don't need to read earnings reports, follow market news, or make any decisions at all. You just buy, hold, and let the arithmetic work in your favor.
If you're skeptical, I encourage you to test this for yourself. Use the comparison tool on this site. Compare the S&P 500 against a selection of actively managed funds, or against individual stocks you might have picked. Look at the long-term results. Notice how the simple, passive approach tends to win over time. The math doesn't lie. The question is whether you're willing to believe it and act accordingly.