The best ETFs for long-term investing

There is not a single best ETF

The title of this article matches a common search. The honest answer does not. No fund is the best long-term holding for every person, every account type, and every horizon. A low-cost S&P 500 tracker can be a core for a buy-and-hold investor who wants large U.S. companies. It is a concentrated, U.S.-only bet for someone who thought they were buying the entire world. A Nasdaq-100 fund can be a deliberate growth tilt. It is a poor stand-in for a diversified core.

Treat "best" as a scorecard you fill in, not as a medal you award. The rest of this article is that scorecard: cost, diversification, tracking, and objective. Examples use funds whose fees were checked against issuer materials on 2026-09-03. Those examples are illustrations of the criteria, not a purchase list and not a ranking.

Criterion 1: cost you will actually pay for years

Long-term investing turns a small annual fee into a large cumulative cost because the fee is charged on a growing base. Expense ratio is the cleanest number to start with: it is published, comparable, and not a forecast of return. It is not the only cost. Trading spreads, premiums or discounts to net asset value, and tracking difference also matter. For a holding you rarely trade, the stated expense ratio is usually the cost that compounds in the background.

Issuer documents, checked 2026-09-03: Vanguard states 0.03% total annual operating expenses for VOO in the S&P 500 ETF summary prospectus dated April 28, 2026. iShares states a 0.03% expense ratio for IVV. State Street states a 0.0945% gross expense ratio for SPY. Invesco states a 0.18% total expense ratio for QQQ (reduced from 0.20% when QQQ moved from a unit investment trust to an open-end structure) and 0.15% for QQQM.

Those five numbers already show why a universal ranking fails. VOO and IVV have the same stated 0.03% cost and track the same S&P 500 index; cost does not separate them. SPY tracks that index at a higher stated cost. QQQ and QQQM track a different, narrower index at higher stated costs than the 0.03% S&P 500 examples. Paying 0.18% for Nasdaq-100 exposure is not "worse" than paying 0.03% for S&P 500 exposure if the investor wanted the Nasdaq-100. It is more expensive for the same index than QQQM's 0.15%, which is a different comparison.

Do not use yield or trailing-return tables as a substitute for the fee line. If you look at past performance on a product page, label it as past. It does not predict the next decade.

Criterion 2: diversification that matches the job

Diversification is not a ticker count. The SEC's investor education treats it as spreading money among holdings whose outcomes do not all depend on the same event. An S&P 500 ETF holds hundreds of large U.S. companies and is still concentrated in its largest names because the index is cap-weighted. A Nasdaq-100 ETF holds fewer names and, by construction, a heavier technology-oriented mix than the S&P 500. Both can be diversified relative to a single stock. They are not diversified relative to each other in the same way.

Ask what would have to go wrong for this fund to fail at its job. If the answer is "U.S. large companies as a group," you own a broad U.S. large-cap fund. If the answer is "the largest non-financial Nasdaq-listed companies," you own a narrower bet. Long-term investors often want the first as a core. The second can be a satellite. Using the second as a core is a concentration choice that should be explicit.

Also ask what you already own. A "best" long-term ETF that duplicates the largest holdings in a workplace target-date fund is not adding a new long-term engine. It is stacking. Look through holdings before you treat a new ticker as diversification.

Criterion 3: tracking the thing you think you bought

Index ETFs are useful when they deliver the index they name. Tracking is the gap between the fund's results and the index's results, driven by fees, sampling, cash, securities lending, and trading around reconstitutions. You do not need a precise tracking-error statistic from a data vendor to use the idea. You need to confirm, from the prospectus and fact sheet, which index the fund follows, whether it holds the index's securities or a sample, and whether the legal structure imposes extra constraints.

Structure shows up here. SPY is a unit investment trust tracking the S&P 500. VOO and IVV are S&P 500 ETFs with a different legal form. QQQ was a UIT and, per Invesco, was reclassified to an open-end fund, which is also the context for the stated expense-ratio change from 0.20% to 0.18%. Those are facts about the wrapper. They are not a forecast of which ticker will "track better" next year, and this article does not invent tracking-difference numbers.

If a fund's objective is active rather than index-tracking, the long-term question changes: you are hiring a process, not buying an index. That can be a reasonable choice. It is a different criterion set — process, capacity, fees, and whether you will stick with the process through underperformance — and it should not be mixed into an index-core decision because a chart looked smoother.

Criterion 4: objective you can still explain in ten years

A long-term holding has to survive boredom. If you cannot explain the fund's objective without the marketing headline, you will not know when to keep it. "U.S. large companies in the S&P 500" is an objective. "Own the future of innovation" is a mood. Moods are expensive to hold through a drawdown in that theme.

Match the objective to horizon and to other income. Equity index funds can fall a long way and stay there longer than a slogan suggests. The SEC's risk-and-return materials are blunt: higher expected return comes with higher risk of loss. A long-term ETF is still an equity (or bond, or mixed) risk. Length of horizon does not remove the risk; it is the reason you might be able to bear it.

Write the invalidation rule. For a core index fund, invalidation is usually a change in your life or in the fund's objective, not a bad year. For a satellite, invalidation might be "this tilt is now larger than I intended" or "I no longer want this concentration." Without that sentence, every decline becomes a referendum on whether the fund was "best."

Buy-and-hold versus frequent trading, taxable versus tax-advantaged

The same ETF can be a reasonable long-term core for one person and a trading vehicle for another. Buy-and-hold investors usually care about the fee that compounds, the breadth of the index, and whether they will still understand the fund after they stop reading about it. Investors who trade often may care more about the liquidity of a particular ticker. Those preferences can point at different S&P 500 wrappers even when the index is the same. They do not produce a universal winner.

Account type changes the cost that dominates. In a tax-advantaged account, the expense ratio and the mix are the main ongoing drags you control. In a taxable account, distributions and realized gains from selling can dwarf a few basis points of expense ratio. That is a location and behavior point, not a tax-optimization product claim. Confirm tax treatment with a tax professional before you sell a large position to "upgrade" to a cheaper share class.

How to use well-known funds as examples, not as a medal stand

S&P 500 examples: VOO, IVV, and SPY all track the S&P 500. On stated cost, VOO and IVV sit at 0.03% and SPY at 0.0945% gross. A long-term buy-and-hold investor who wants that index will usually care about the lower holding cost and about operational details at their brokerage (whether the fund is available in a workplace plan, commission schedule, and whether they already own one of them). A frequent trader might still look at SPY because of how that market trades. Neither sentence is a recommendation.

Nasdaq-100 examples: QQQ at 0.18% and QQQM at 0.15% track the same index. The long-term question is whether you want that index at all as a large weight. If you do, the 0.03-percentage-point gap is a cost difference between twins, not evidence that Nasdaq-100 beats the S&P 500. If you do not, neither ticker belongs in the "long-term core" slot.

What this article does not do: rank funds by past return, quote a yield table, or declare a winner for 2026. Those exercises age badly and they train you to chase the last cycle.

A selection process you can repeat

Name the job of the money and the role of the fund (core, ballast, or satellite).

Read the objective and the index in the prospectus, not the nickname on a charting site.

Check diversification against what you already own, including look-through of other funds.

Record the stated expense ratio from the issuer on a dated source, and re-check it when you review the portfolio.

Note structure (open-end ETF versus UIT, share class twins) only as it affects cost, constraints, or how you will trade.

Ignore long performance leaderboards except as history, explicitly not as a forecast.

Write the condition that would make you sell, other than "it went down."

Common mistakes in "best ETF" lists

Treating last decade's return as a quality score. Indexes go in and out of fashion as a group.

Calling a concentrated index a diversified long-term portfolio because it holds more than one stock.

Buying three "best" funds that share a top-ten list.

Switching cores every year to the new list, which turns a long-term plan into a taxable trading plan.

Using expense ratio as the only filter while ignoring that the cheap fund tracks a different, narrower index.

Assuming the fund in a workplace plan is inferior because a blog preferred a different ticker; availability and existing holdings matter.

What "best" should mean for you

For long-term investing, "best" is the fund you can explain, hold, and rebalance: clear objective, diversification that matches that objective, tracking of the stated index, and a cost that is not a quiet leak. On those criteria, a 0.03% S&P 500 tracker and a 0.18% Nasdaq-100 tracker are not competitors. They are different jobs. The S&P 500 twins at 0.03% versus 0.0945% are closer competitors on exposure, and even then the better wrapper depends on whether you are holding for decades or trading the ticker, and on where the shares sit.

If you already own a mix, the higher-leverage step is usually measuring it — sector weights, overlap, and whether the largest issuers appear in several wrappers — rather than adding the next fund from a list. StockLift can help you analyze a linked portfolio. It does not execute transactions.