How much does a fund's fee actually cost you?
A 1% expense ratio sounds small next to a 7% annual return. Compounded over 30 years, it isn't — it's often the single biggest cost in an investing lifetime, and it's the one cost that's entirely visible and entirely avoidable before you invest a dollar.
The comparison
Two identical starting balances, the same contributions, the same gross return — the only difference is what each fund charges every year. Drag anything below and watch the gap.
Starting with $4,000 and adding $0 a year, at 7% annual returns before fees — compared at 0.05% versus 3.1% in annual expenses.
Chart explanation
Here's what that looks like for one investor: you put in $4,000, and both funds grow 7% a year before fees. After 30 years, the 0.05% fund is worth $30,025. The 3.1% fund — same money, same growth, just a higher fee — is worth $12,605: $17,421 less, purely from the fee. Put another way: the 3.1% fee fund needs 53 years of investing to reach what the 0.05% fee fund already has after just 30 — 23 extra years of saving for the same result.
Assumes both funds hold the same underlying assets and earn the same gross return before fees — the entire gap shown is the expense ratio, nothing else.
Is this a realistic comparison?
These aren't a cheap ETF versus a strawman. Every fund below exists to do the same job — track the S&P 500 — and says so in its own prospectus. The mutual fund rows are the same index, sold at a very different price.
| Fund | Ticker | Type | Expense ratio | |
|---|---|---|---|---|
| State Street SPDR Portfolio S&P 500 ETF | SPYM | ETF | 0.02% | |
| Vanguard S&P 500 ETF | VOO | ETF | 0.03% | |
| iShares Core S&P 500 ETF | IVV | ETF | 0.03% | |
| SPDR S&P 500 ETF Trust | SPY | ETF | 0.0945% | |
| Rydex S&P 500 Fund, Class A | RYSOX | Mutual fund | 1.59% | |
| Rydex S&P 500 Fund, Class C | RYSYX | Mutual fund | 2.35% |
Every fund here states the same goal in its own prospectus: match the S&P 500 index, before fees. The Rydex fund isn't actively managed differently from the ETFs above — it's the same index, sold through a channel that charges 50–100x more for it. Figures reflect fund prospectuses/fact sheets as of 2026; expense ratios change, so check current figures before acting on them.
What about actively managed funds, or a “prime” account?
The table above is the cleanest case: identical holdings, so a higher fee can't be buying you anything except a worse result. Actively managed funds are a fuzzier pitch — the manager is buying different stocks, or trying to time the market, so in principle the extra fee is paying for something. In practice, the data doesn't back that up: independent studies that track active fund performance against their own benchmark (S&P's SPIVA reports are the best-known) consistently find that most actively managed U.S. equity funds underperform their benchmark index over 10- and 15-year periods, after fees. The fee isn't a fixed cost you're weighing against a likely payoff — it's a bet that loses more often than it wins.
The same math applies to anything sold as a bundle: a “prime” or advisory wrap account that layers a 1%+ annual advisory fee on top of the underlying funds' own expense ratios, or a load fund that takes a cut (sometimes 5% or more) the moment you buy in, before a single dollar has had the chance to grow. None of that shows up as a dramatic number in any one year — it shows up exactly like the gap in the chart above, compounding quietly for decades.
What the model does and doesn't account for
It compounds each balance at the gross return minus its own expense ratio, adding the same annual contribution to both sides. It doesn't model any difference in the funds' actual holdings, tracking error, or tax treatment — see the index vs. active lesson for the tax side of that comparison. See the About & methodology page for more on how these lessons are built.