What is an index fund?

An index fund is a basket of stocks that automatically owns a little piece of hundreds or thousands of companies at once. Instead of picking individual stocks, you buy the whole market in a single transaction.

Think of it like buying the entire buffet instead of trying to guess which dishes are best. You get everything — the winners, the losers, and everything in between. And here's the surprising part: that "everything" strategy beats most people who spend their careers trying to pick just the winners.

An index is just a list. The S&P 500 is a list of the 500 largest publicly traded companies in the US. The Total Stock Market index is a list of essentially every public US company — over 3,500 of them.

An index fund is a fund that buys every stock on that list, in the exact proportions that match the index. If Apple makes up 7% of the S&P 500, the fund puts 7% of your money into Apple. If some tiny company makes up 0.01%, it gets 0.01%. The fund just mirrors the list.

When you buy an index fund tracking the S&P 500, you instantly own a piece of Apple, Microsoft, Amazon, Google, Nvidia, Tesla, Johnson & Johnson, Visa, and 493 other companies. You didn't have to research them. You didn't have to time your purchase. You just own all of them.

Some of those companies will fail. Some will stagnate. But others will become the next Apple or Amazon — and because you own everything, you capture those wins automatically. You don't need to predict the future. You just need to participate.

Most mutual funds are actively managed — a team of professionals picks stocks they think will outperform. Sounds smart, right? The problem: it rarely works.

Over any 15-year period, roughly 90% of actively managed funds fail to beat the S&P 500 index. Not because the managers are bad — they're not. It's because beating the market is really, really hard. And expensive. And often just luck.

The most common ones are based on the S&P 500 (large US companies) or the Total Stock Market (all US companies). Here are the big ones:

All three are excellent. The difference in long-term performance is minimal. Pick one and move on. Seriously — this is one of those decisions where overthinking costs you more than the wrong choice ever would.

A 0.03% fee means you pay $3 per year for every $10,000 invested. A 1.5% fee (common for actively managed funds) means you pay $150 per year for the same $10,000.

That difference compounds. Over decades, high fees don't just reduce your returns — they devastate them. Index funds keep your fees so low that almost all of the market's growth goes to you, not to fund managers.

That's it. You just did what most financial advisors would charge 1% per year to do for you. And you'll probably end up with more money because you're not paying them.