Choosing Your Index Funds

You have a goal. You have a mix. Now you buy the things.

This is the step everything else was setting up, and it is smaller than you'd expect. You are going to buy one fund for each major piece of your asset allocation — your split across asset classes: a U.S. stock fund, an international stock fund, and a bond fund. Three funds. That's a complete, diversified retirement portfolio, and it is not a beginner's compromise that you graduate out of later. Plenty of people who have done this for forty years own exactly that.

Video coming soon

This lesson explains the idea in full without it.

Later, if you want, you can add more. Individual stocks, more specialized funds, other asset classes. None of that is required and none of it is where the returns come from. The three-fund version gets you the parts that matter — broad ownership, low cost, a mix you chose on purpose — and it fits on an index card.

The first real decision is what kind of fund you're buying.

Two philosophies, two kinds of fund

Every fund is somebody's answer to one question: should we try to beat the market, or just own it?

An actively managed fund is a fund where a manager picks the investments, aiming to beat an index. There's a person, or a team, reading filings and forming opinions about which companies will do well and when to buy them. They get paid to have those opinions.

An index fund is a fund that holds everything in an index instead of picking winners. There's nobody forming opinions. The index says these companies, in these proportions; the fund buys them and holds them. Its benchmark — the index it measures itself against — isn't a target to beat. It's a target to match.

That difference sounds philosophical. It shows up as a number on your statement.

What you get from an active manager

Be fair to active funds, because they do things index funds can't.

Some pursue a strategy that has no index — trying to make money when markets fall, reaching into assets that aren't publicly traded, or holding only companies that meet a standard you care about. If you specifically want that, an index fund won't give it to you.

The most common one you'll actually meet is the target-date fund, sometimes called a lifecycle fund. You pick the fund named for roughly when you'll retire and a manager runs the allocation for you — heavy in stocks while you're young, drifting toward bonds as the date approaches. It's the default in a lot of 401(k) plans, sometimes literally the fund your money lands in if you never choose. That's a real service. It's doing the job this course is teaching you to do yourself.

What an index fund actually holds

An index fund's contents are just its index. A fund tracking the S&P 500 holds around 500 companies; one tracking the Dow Jones Industrial Average holds about 30.

But not in equal slices. The S&P 500 is weighted by market capitalization — a company's total value, share price times shares outstanding — so the biggest companies take up the most room. An S&P 500 index fund is not 500 equal bets. It's much more exposed to the handful of giants at the top of the list than to the smallest name in the index, where a single dollar barely registers. Which companies sit at the top changes over time; that the top is heavy doesn't. Any fund publishes its largest holdings on its own page, and it's worth a look before you assume 500 names means 500 bets. (The Dow is odd: it weights by share price instead, which is a historical quirk more than a design.)

This matters for a reason people miss: index fund does not automatically mean diversified. A fund tracking the Nasdaq Composite is an index fund, and it's heavily concentrated in technology. Buying the list is only as good as the list. Read what's in it.

Which one is right?

Wealth managers argue about this loudly and there's no verdict that fits everyone. But the honest version of the argument is more interesting than the shouting.

Video coming soon

This lesson explains the idea in full without it.

Start by clearing away a bad argument you'll hear from our side. It is not that active managers are stupid or lazy. Many are extraordinarily capable people working extremely hard. That's actually the problem.

Here's the real shape of it. An active manager doesn't need to beat the index. They need to beat the index by more than they charge you — every year, forever. If a fund charges 1% a year more than an index fund does, matching the index leaves you a full percentage point behind. Doing well isn't enough; doing well by enough to cover the toll is the bar. And from Rule 2, you already know what a percentage point does over a working life: it isn't a haircut, it compounds against you, and it can cost roughly a fifth of your final balance over forty years.

Now ask who's on the other side of the manager's trades. Not amateurs — other professionals, equally credentialed, with the same filings and faster computers. When a manager buys a stock convinced it's cheap, someone just as smart sold it convinced it wasn't. The collective effect is that most of what's knowable about a company is already in its price. Eugene Fama built a career on that observation: if an expert really knew a stock was about to soar, she'd buy it, and her buying would push the price up until the bargain was gone.

The economist Tobias Moskowitz put it with a jar of jelly beans. Ask a crowd to guess how many are inside and the individual guesses are all over the place — wildly high, wildly low. Average them, and the average lands close to the truth. A stock's price is that average: what everyone willing to trade it has collectively concluded it's worth. You can beat the crowd. It's just hard to do it repeatedly, and harder to prove you didn't get lucky.

When researchers have measured this at scale, the finding has been unkind to active funds. The pattern that keeps showing up is that after fees, only a small minority beat their index over long periods — and knowing which ones, in advance, is the part nobody has solved.

That last clause is where the argument actually lives. Some active funds will beat their index over the next thirty years. That's certain. The trouble is that you have to pick them now, and last decade's winners are a famously poor guide to next decade's. Past performance isn't a promise from anybody — not from an active manager, and not from an index fund either.

So here's the case for indexing, stated without triumph. Nobody knows which funds will win. Nobody knows what the market will do. But you know exactly what a fund charges, today, in writing. When almost everything is unknowable and one thing is knowable and it compounds, you pay attention to the knowable thing.

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That's also the honest limit of an index fund. It doesn't beat its index. It can't. Chart an index fund against its benchmark and the two lines move together almost perfectly — with the fund finishing a hair behind. That gap is the fee. You are not buying outperformance. You are buying the market's return minus a very small toll, instead of paying a large toll for a shot at more.

Loads: a fee taken off the top

Some mutual funds charge a load — a sales charge, separate from the annual expense ratio.

A front-end load comes out when you buy. Put $1,000 into a fund with a 5% front-end load and $50 goes to the sales charge; $950 gets invested. You're down 5% before the market does anything at all, and you're not just missing $50 — you're missing everything that $50 would have earned for the next thirty years.

A back-end load is charged when you sell, and usually shrinks the longer you hold the fund.

No-load funds exist and are widely available. Be careful, though: no-load doesn't mean free. A no-load fund may still involve a flat trading commission, and it definitely still has an expense ratio — the annual fee, charged as a percent of your money, every year, whether the fund gains or loses. A load is a one-time bite. The expense ratio is the one that never stops. Check both, and don't let a fund with no load talk you out of reading its expense ratio.

How stock funds get labeled

Fund names are built from two ideas: size and style. Once you can read them, the fund menu stops looking like alphabet soup.

Size means market cap

Market cap is share price times shares outstanding. Say fictional company XYZ has 2 billion shares trading at $50 — round numbers, chosen to be easy, not real. Its market cap is $100 billion. That's the company's whole price tag, which is a much better measure of size than share price alone.

Funds sort companies into three buckets by that number:

The dollar cutoffs between the buckets aren't fixed by anyone. Different fund companies draw the lines in different places, and everyone moves them up as the market grows, so treat the buckets as a rough sorting rule rather than a law. If a cutoff matters to you, the fund's own factsheet will tell you where it drew the line. The major indices you already know are dominated by large caps.

Style means how the fund picks

Growth investing buys companies expected to grow earnings or revenue quickly. Value investing buys companies that look cheap relative to what the business seems to be worth — solid financials, a price that hasn't caught up. There are indices for each, so you'll find funds tracking, for instance, the growth half of the S&P 500 or the value half.

A third label, blend, means both. If your goal is to own as much of the market as possible — and for a first portfolio, it's a reasonable goal — blend is the one that doesn't leave half the market out.

Combine the two and you can read any fund name: large-cap value, small-cap growth, large-cap blend. A plain S&P 500 index fund is a large-cap blend fund. Most first portfolios start there.

Finding funds for your portfolio

Now the actual shopping. Below are indices you'll see funds tracking. You aren't choosing a fund here — you're choosing which list you want to own, and then finding a low-fee fund that tracks it. Many funds track each of these indices, from many different companies. That's the good news: the index is what determines what you own, so your job narrows to finding a fund that tracks the index you want and charges as little as possible to do it.

A note before the tables. Every constituent count below moves. Companies get added, dropped, merged, and go public. That churn is the index doing its job — none of it changes what the index is for, and none of it should change your decision.

Domestic equity: owning the U.S. market

Two of those rows deserve a footnote, because both look like paradoxes and neither is one.

The Russell 2000 holds two-thirds of the companies in the Russell 3000 but only a small fraction of its market value. That's not an error. It's what market-cap weighting means: 2,000 small companies added together are still small next to a few hundred giants. Counting companies tells you almost nothing about how much of the market you own.

And the Wilshire 5000 holds fewer companies than its name advertises. The source of that name was the count at launch, and the number of U.S. public companies has fallen since. It's a stale label on an index that still does exactly what it claims: hold the whole U.S. stock market. Whatever the count happens to be on the day you look, that count is the whole market. An index is a rule, not a headcount — and if you want the current number, the index provider publishes it.

That's the general lesson for this entire section. Don't agonize over which of these is the "right" index. They overlap heavily and they move together. Pick a broadly diversified one and spend your attention on the expense ratio — that's the part of this decision that actually shows up in your balance.

International equity: owning everywhere else

The U.S. is a large share of the world's stock market. It is not all of it, and it has had long stretches of trailing the rest. That's the entire argument for an international fund: you don't know which region wins the next twenty years, so own them all.

Individual countries have their own indices — Japan's Nikkei 225, the U.K.'s FTSE 100 (the "Footsie"). Buying one fund per country would be absurd. Instead there are broad international benchmarks, several of the best-known published by MSCI. Exactly how many companies and countries each one covers shifts as markets are added and reclassified; MSCI publishes the current figures on each index's factsheet, and that's where to look if the number matters to you.

Learn to read two words in a fund's name, because they decide what you actually own:

• ex-USA means U.S. companies are excluded. If you already hold a U.S. fund, that's usually what you want — no accidental doubling up.
• World is not literal. MSCI World ex-USA covers developed markets only, despite the name. Global, without "ex-USA," usually includes the U.S.

Developed and emerging markets behave differently — emerging markets have historically offered more growth and rougher rides. Holding both is broader than holding either. Whether you get that from one ACWI ex-USA fund or by pairing two funds is a matter of preference and cost, not correctness.

Bonds: owning the loans

You already know bonds: you lend money, you collect interest, you get your par value back at maturity. You know the three big issuer types — government, municipal, and corporate — and that maturities range from months to decades.

A bond index fund is how you own a lot of that at once, across issuers and across maturities, without picking individual bonds. And there are indices that slice bonds narrowly — only Treasuries, only short maturities — but for a first portfolio, the broad ones are the point.

A naming quirk worth knowing: these two benchmarks are published under a bank's brand, and that brand has changed more than once as the index changed hands. You'll see the same index referred to by different company names in material written in different decades. Match on what the index actually covers — U.S. taxable bonds, or global ones — rather than on whose name is attached to it this year. A fund's description will tell you which index it tracks.

A fund tracking either one gives you a wide mix of issuers and maturity dates in a single purchase. That's the whole reason to use one: diversifying bonds by hand means buying a lot of individual bonds, and a fund does it for you.

One difference worth remembering from the bond lesson: a bond fund has no maturity date. Individual bonds mature and repay you; a fund keeps buying new ones as old ones mature, so it never hands your principal back on a date. That's not a flaw — it just means a bond fund's price moves with interest rates indefinitely, rather than pulling toward par as a maturity approaches.

Cash

Most portfolios don't need a cash allocation until a goal is getting close. If yours does, the tools are the ones you've already met: a certificate of deposit (CD) — a bank deposit at a fixed rate for a fixed term — or a Treasury bill, plus whatever uninvested cash sits in your account.

The one rule that matters here: match the maturity to the need. Choose CDs or T-bills that mature comfortably before you plan to spend the money. Cash you have to break early to reach isn't doing the job cash exists to do.

What you actually do

Pick your three lists. Find a fund tracking each one. Compare expense ratios, check for a load, and buy the cheapest fund that tracks the index you want.

That's it. There's no step you're missing. The reason this feels too simple is that most investing content is selling something more complicated — and the more complicated thing usually costs more, which is the one variable we know works against you.

Two honest caveats. This is a general approach to a common goal, not advice about your situation. And nothing here promises a return: a diversified index portfolio will have losing years, and losing stretches long enough to test you. What it does is give you broad ownership at the lowest cost available, which is the part of the outcome you get to decide.

Key takeaways

• A three-fund portfolio — U.S. stocks, international stocks, bonds — is a complete, diversified retirement portfolio. It isn't a starter kit you outgrow.
• An active fund has to beat its index by more than its fee, every year, to be worth choosing. Some will. Identifying them in advance is the part nobody has solved.
• Fees are the one variable you can know in advance and control. When everything else is unknowable and this compounds against you, it's where your attention belongs.
• Index fund doesn't mean diversified — a Nasdaq fund is an index fund and is concentrated in tech. Read the list before you buy it.
• Constituent counts and thresholds drift, and index names go stale (the "Wilshire 5000" holds fewer than 5,000). An index is a rule, not a headcount. Judge the rule and the expense ratio.