Best S&P 500 ETFs

The S&P 500 is an index of roughly 500 of the largest US companies, weighted by market value, covering something like 80% of the total US stock market by capitalization. Its biggest names are the mega-caps that dominate the market: Apple, Microsoft, Nvidia, Amazon, Alphabet, and Meta. When people say “the market” in the US, they usually mean the S&P 500.

It is the default US core because it is broad, cheap to track, and historically the benchmark almost every active fund is measured against (and that most fail to beat over long periods). An S&P 500 ETF gives you one ticker holding those 500 companies, automatically rebalanced as the index changes, at a near-zero fee. That is why it sits at the center of so many portfolios. A total-market fund like VTI goes one step broader by adding the mid- and small-cap tail; the full comparison of that choice is in our best total stock market ETFs guide.

VOO (Vanguard S&P 500 ETF) and IVV (iShares Core S&P 500 ETF) are the two funds most long-term investors reach for. Both track the same S&P 500, both cost around 0.03%, and both have very tight tracking, so their returns are nearly indistinguishable. VOO is the most-held S&P 500 ETF among long-term retail investors and one of the largest funds in the world by assets; IVV is iShares' near-twin.

Because VOO and IVV are functionally identical, the choice between them is provider preference, not performance. People who already use Vanguard or favor its mutual-fund-and-ETF lineup pick VOO; people in the iShares or BlackRock ecosystem pick IVV. Holding both would simply duplicate the same exposure at the same fee. For either, the relevant fact is the same: ~0.03% buys you the entire large-cap US market in one ticker.

SPY (SPDR S&P 500 ETF) is the original. It launched in 1993 as the first US-listed ETF and remains the most heavily traded fund in the market, with the deepest order book and by far the largest options market. That liquidity is its reason to exist: traders, institutions, and options sellers use SPY precisely because it is so easy to move size in and out and to build options strategies around.

The trade-off is cost. SPY charges around 0.0945%, roughly triple VOO and IVV, because of its older structure and its positioning as the trading vehicle rather than the cheap buy-and-hold fund. For a long-term holder, the extra fee buys liquidity they will never use, so SPY is usually the wrong default for retirement-style holding. For an active trader or options user, it is often the right tool. State Street even sells the cheap version separately, which is SPLG below.

If the only thing you care about is the lowest fee, SPLG (SPDR Portfolio S&P 500 ETF) is the cheapest S&P 500 ETF at around 0.02%. It is State Street's low-cost answer to VOO and IVV: same S&P 500 index, same holdings, lower expense ratio than its own SPY, built for buy-and-hold investors rather than traders. It is smaller and less liquid than SPY, but for long-term holding that does not matter.

Outside the ETF wrapper, FXAIX (Fidelity 500 Index Fund) is the mutual-fund version of the same exposure at around 0.015%, the cheapest of the group. It is a common default for investors who hold everything at Fidelity, especially inside 401(k) and IRA accounts where mutual funds are easier to buy in dollar amounts. The practical point: the cost gaps between SPLG, FXAIX, VOO, and IVV are tiny, so liquidity and ecosystem usually decide more than the last basis point of fee.

This is the core takeaway: every S&P 500 ETF tracks the same index, owns the same companies in the same weights, and delivers nearly identical returns before fees. There is no secret edge in one over another. What actually differs is three things. Cost: VOO and IVV at ~0.03%, SPLG at ~0.02%, FXAIX at ~0.015%, SPY at ~0.0945%. Liquidity: SPY is deepest, which only matters for active trading and options. Provider: Vanguard, iShares, State Street, or Fidelity, which usually comes down to the broker you already use.

So the decision is short. For long-term holding, pick the cheap one that fits your broker (VOO, IVV, or SPLG). For active trading or options, pick SPY for its liquidity. And do not hold more than one, because that just stacks identical exposure at different fees. If you want to widen the circle beyond the largest 500 companies, a total-market fund is the next step; if you want to think about which fund fills which slot in a whole portfolio, see our best ETF in every category guide.

Expense ratios are approximate as of early 2026; verify the current figure on each issuer's site. FXAIX is a mutual fund rather than an ETF, so it trades once a day at net asset value instead of intraday. Notice how little separates these funds: the holdings are identical, so the table really compares fees and providers, not the underlying exposure. For more on reading these numbers, see how to compare ETFs.

Because the S&P 500 funds are near-identical, the real questions are about your own portfolio, not the fund: do I already hold S&P 500 exposure somewhere (inside a target-date fund, a robo portfolio, or a total-market ETF), how much would this overlap with what I own, and which of these fits the broker I use. Those are questions an AI assistant can answer when it can see your real holdings, rather than a generic ranking.

That is where Walnut fits. It connects your existing brokerage through SnapTrade and lets you ask, in plain language through Claude, ChatGPT, or a built-in assistant, whether a new S&P 500 fund overlaps with what you already own, which of VOO, IVV, SPLG, or SPY suits your account, and how each one has tracked the index. It is read-only by default, and you approve any trade. Walnut is not an investment adviser; it helps you see and act on your own portfolio rather than telling you what to buy. For a broader 2026 shortlist, see our best ETFs to invest in for 2026 guide.

Every S&P 500 ETF tracks the same index, so the comparison is about cost, liquidity, and provider, not performance. For long-term holding, VOO and IVV at ~0.03% are the standard picks, and SPLG at ~0.02% is the cheapest ETF, with Fidelity's FXAIX mutual fund at ~0.015% for Fidelity accounts. SPY is the original and most liquid, worth its higher ~0.0945% fee only if you trade actively or use options. Holding more than one is redundant, because they are the same exposure.

From a connected account you can dig into any of these as an ETF, look at an individual stock the index holds, or explore a theme you want extra exposure to. Expense ratios and fund details change over time; treat the figures here as a starting point and confirm on each provider's site before deciding.