Quick recap: SPY is "a fund that tracks the S&P 500." This lesson is about what a fund actually is — because funds, not individual stocks, are how I invest almost everything.
The bundle
A fund pools money from lots of people and buys a big basket of stocks. Own a piece of the fund, and you own a piece of everything inside it. One purchase, instant variety. That variety has a name — diversification — and it means no single company can sink you. If one of 500 companies has a terrible year, you barely feel it.
ETF vs. mutual fund
Two wrappers for the same idea:
- An ETF (exchange-traded fund) trades on an exchange all day with a ticker — SPY and QQQ are ETFs. This is the modern default.
- A mutual fund is the older wrapper: you buy in once a day at the closing price. Common in 401(k)s.
For a beginner the differences barely matter. What matters is what's inside and what it costs. A fund's fee is its expense ratio — good broad index funds charge 0.1% a year or less. Cheap matters, because fees compound against you just like returns compound for you.
Why not just pick the winners?
Because almost nobody can — reliably, for decades. Most professional fund managers fail to beat the plain S&P 500 over long periods, and they do it full-time. An index fund skips the guessing: hold everything, ride the average. And the average is good! Broad U.S. stocks have returned roughly 10% a year over the long run — with huge swings along the way, which is exactly what the next lessons teach you to look at calmly.
My approach in one line: own everything, cheaply, forever.
Terms you now know
- Fund — a pooled basket of many stocks bought as one thing.
- ETF — a fund that trades all day under a ticker.
- Mutual fund — a fund you buy once a day at the closing price.
- Index fund — a fund that just copies an index instead of picking stocks.
- Diversification — spreading money across many companies.
- Expense ratio — a fund's yearly fee.
Check yourself
One company in your 500-stock index fund goes bankrupt. Roughly what happens to you?
Almost nothing — it was one of 500 holdings. That's diversification doing its job.
Why do I default to index funds instead of picking stocks?
Because even most professionals fail to beat the index over long periods. Holding everything cheaply captures the market's growth without the guessing.