Four ETFs, one index. For a long-term retirement saver the real differences are a few hundredths of a percent in fees and one old fund structure. Here is what each one costs, how SPY’s trust rules differ, and when switching is a mistake.
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If you are investing for retirement and plan to hold for decades, VOO, IVV and SPYM do the same job at almost the same cost, so the brokerage you already use is a fine tiebreaker. SPY is the outlier: built in 1993 as the first US ETF, it keeps an older trust structure and a higher fee, which suits active traders more than savers.
Scope: US-listed S&P 500 index ETFs held by a US investor in a 401(k) brokerage window, IRA or taxable account. Excluded: the equal-weight version (see RSP vs VOO), total-market funds (see VOO vs VTI), mutual-fund share classes and leveraged S&P 500 funds. Education, not advice for your situation.
| Your situation | Fits | Why |
|---|---|---|
| Long-term saver, any broker | VOO, IVV or SPYM | Same index, 0.02%–0.03% a year |
| Lowest possible fee | SPYM (0.02%) | $10 a year less than VOO per $100,000 |
| You trade options or move in and out during the day | SPY | Deepest trading volume of the four |
| You already own SPY in a taxable account with big gains | Keeping it usually wins | Tax on selling dwarfs the fee saving |
| You own SPY in an IRA or 401(k) | Switching costs no tax | A cheaper twin saves 0.06–0.07 points a year |
They hold the same roughly 500 companies, so the table is mostly about cost and plumbing. Fees, index, holdings and 10-year NAV returns (to Sep 30, 2026) from each issuer; SPY/SPYM assets, volume, distribution yields and calendar-year returns from Exent market data on the dates shown.
| VOO | IVV | SPY | SPYM | |
|---|---|---|---|---|
| Issuer | Vanguard | iShares | State Street | State Street |
| Index | S&P 500 | S&P 500 | S&P 500 | S&P 500 |
| Structure | Open-end ETF share class | Open-end ETF | Unit investment trust | Open-end ETF |
| Expense ratio | 0.03% | 0.03% | 0.0945% | 0.02% |
| Holdings | 505 (Sep 30, 2026) | 504 (Oct 23, 2026) | 504 (Sep 30, 2026) | 505 (Sep 30, 2026) |
| Assets | $1,032B ETF / $1,732B fund (Sep 30) | $874B (Oct 23) | $811B (Oct 25) | $182B (Oct 25) |
| ETF launched | Sep 2010 | May 2000 | Jan 1993 | Nov 2005 |
| Share price, Oct 23, 2026 | $698.58 | $763.25 | $759.97 | $89.45 |
| Shares traded, Oct 23, 2026 | 4.6M (≈$3.2B) | 4.2M (≈$3.2B) | 33.1M (≈$25.2B) | 15.8M (≈$1.4B) |
| Distribution yield, trailing 12 months (to Sep 30) | 1.06% | 1.10% | 0.99% | 1.01% |
| 10-year return, per year (NAV, to Sep 30, 2026) | 15.29% | 15.30% | 15.18% | 15.31% |
| 2022 calendar-year return | −18.2% | −18.2% | −18.2% | −18.1% |
All four compounded at 15.2% to 15.3% a year over the decade, with SPY lowest by about its extra fee, and the calendar-year returns from 2017 to 2025 never differed by more than 0.8 percentage points (2019: SPYM 32.0% vs SPY 31.2%, Exent market data). Vanguard’s fact sheet shows how small tracking costs are: VOO’s 10-year NAV return was 15.29% a year against 15.33% for the S&P 500 itself, a gap close to its fee. One-day volume is a single snapshot, not an average.
Because SPY is a unit investment trust with rules written in 1993, while the other three are ordinary open-end funds. State Street’s page describes SPY as “a unit investment trust,” and its prospectus dated Jan 26, 2026 spells out what that means in practice:
What SPY offers in return is liquidity. On Oct 23, 2026 it traded about eight times VOO’s dollar volume, and State Street’s page notes that options are available on it. That matters to traders who need tight prices for large orders or options strategies; for someone adding $500 a month to an IRA, the other three already trade billions of dollars a day. The Nasdaq-100’s QQQ shed the same trust structure in Dec 2025 (see QQQ vs VOO); SPY has not.
Yes, SPYM is the same fund that used to trade as SPLG. A supplement filed by SPDR Series Trust on Oct 21, 2025 announced that the SPDR Portfolio S&P 500 ETF would become the State Street SPDR Portfolio S&P 500 ETF and change its ticker from SPLG to SPYM, effective Oct 31, 2025. The index, holdings and 0.02% fee carried over, and old SPLG shares simply show up as SPYM in brokerage accounts. If an old article or a 401(k) window still says SPLG, it means SPYM.
SPYM’s low share price (about $89 vs $698 for VOO on Oct 23, 2026) once mattered when brokers did not sell fractional shares. Most large brokers now do, so price per share is rarely a reason to choose one fund. See SPYM’s data page for current figures.
Tens of thousands of dollars on a large balance over decades, and almost nothing in a single year. Exent calculation, illustrative: $300,000 in an IRA, a constant 7% yearly return before fees, no further contributions, 30 years, ending value = 300,000 × (1.07 − fee)^30.
| Fund | Fee | First-year cost | Value after 30 years | Gap vs SPYM |
|---|---|---|---|---|
| SPYM | 0.02% | $60 | $2,270,905 | — |
| VOO or IVV | 0.03% | $90 | $2,264,546 | −$6,359 |
| SPY | 0.0945% | $284 | $2,223,938 | −$46,967 |
| Fund | SPYM | VOO or IVV | SPY |
|---|---|---|---|
| Fee | 0.02% | 0.03% | 0.0945% |
| First-year cost | $60 | $90 | $284 |
| Value after 30 years | $2,270,905 | $2,264,546 | $2,223,938 |
| Gap vs SPYM | — | −$6,359 | −$46,967 |
The 7% return is an assumption, not a forecast. The point is the ratio: between the three cheap funds the difference is a rounding error, while SPY’s higher fee costs about 2% of the ending balance. The SEC’s Investor.gov shows the same effect at larger fee gaps: $100,000 growing 4% a year for 20 years ends near $208,000 with a 0.25% fee and $179,000 with 1.00% (Investor.gov).
| Fund | Pros | Cons |
|---|---|---|
| VOO | 0.03% fee; full replication with a 10-year tracking gap of 0.04 points a year (Vanguard); part of a $1.7 trillion fund, so closure risk is remote. | High share price if your broker lacks fractional shares; 0.01 point a year more than SPYM; the ETF is one share class of a larger fund, so its own assets ($1,032 billion) are smaller than the headline fund figure. |
| IVV | 0.03% fee; $874 billion in assets; the S&P 500 option inside many iShares model portfolios. | Same high share price issue; no real advantage over VOO beyond broker preference. |
| SPY | Oldest and most traded S&P 500 ETF; large options market; holds substantially all S&P 500 stocks at index weights. | 0.0945% fee, about three times VOO; trust cannot reinvest dividends or lend securities; idle dividend cash earns no interest for holders. |
| SPYM | Lowest fee of the group (0.02%); low share price; same index and holdings as the others. | Smallest of the four ($182 billion); the 2025 rename can confuse older statements and articles that still say SPLG. |
If you want more than the 500 largest companies, or a different weighting, these are the nearest neighbors. Expense ratios and holdings from the issuers (Vanguard Sep 30, iShares Oct 22–23, Schwab Oct 22, 2026):
| ETF | What it holds | Expense ratio | Holdings | Difference vs an S&P 500 fund |
|---|---|---|---|---|
| VTI | Whole US market | 0.03% | 3,519 | Adds about 3,000 mid and small companies |
| ITOT | Whole US market, S&P index | 0.03% | 2,442 | Same idea as VTI from iShares |
| SCHX | US large caps, Dow Jones index | 0.03% | 754 | About 250 more large companies |
| VXF | US market minus the S&P 500 | 0.05% | 3,359 | Pairs with an S&P 500 fund to rebuild the total market |
| RSP | S&P 500, equal weight | 0.20% | 505 | Same companies, top 10 at about 3% instead of about 41% |
When the old fund sits in a taxable account with large gains. Counterexample, illustrative with federal rates from IRS Topic 409: you hold $150,000 of SPY bought for $60,000. Selling realizes a $90,000 long-term gain; at the 15% rate that is $13,500 of federal tax. Moving the remaining $136,500 to VOO saves 0.0645% a year, about $88 ($136,500 × 0.0645%). Because both funds grow at the same market rate, the smaller balance catches up only through that fee gap: (150,000 ÷ 136,500)^(1/n) − 1 = 0.0645% gives n = ln(1.0989) ÷ ln(1.000645) ≈ 146 years, far longer than any retirement. Inside an IRA or 401(k) the same switch has no tax cost, so it can make sense there.
The bigger question is usually elsewhere. A saver who owns an S&P 500 fund, a Nasdaq-100 fund and a few large tech stocks holds one concentrated bet three times; see how concentrated the S&P 500 is and how much VOO, QQQ and VTI overlap. And a 60-year-old fully in stocks gains nothing from picking SPYM over SPY compared with deciding how much belongs in bonds (see how to choose ETFs for retirement).
Over the 15 years to June 30, 2026, 90.49% of actively managed US large-cap funds underperformed the S&P 500 (S&P DJI, SPIVA), and any of these four ETFs holds that index for a few hundredths of a percent.
Yes. State Street renamed the SPDR Portfolio S&P 500 ETF and changed its ticker from SPLG to SPYM effective Oct 31, 2025. The index, holdings and 0.02% fee did not change.
Neither has an edge. Both track the S&P 500 at 0.03% and returned 15.29% (VOO) and 15.30% (IVV) a year over the 10 years to Sep 30, 2026 (issuer NAV). The one your broker trades without commission is a fine tiebreaker.
SPY is a 1993 unit investment trust with a 0.0945% expense ratio, versus 0.03% for VOO. Its trust rules also stop it from reinvesting dividends between payouts or lending securities.
Only by 0.01 percentage point, or $10 a year per $100,000. Over 30 years on $300,000 at an assumed 7%, that is about $6,000. Either is a reasonable core holding.
No. Its prospectus says the trust provides no dividend reinvestment; dividends sit in a non-interest-bearing account until paid quarterly. Your broker can still reinvest your payouts for you.
Usually not if you have large gains. Illustrative: a $90,000 gain taxed at 15% costs $13,500, while the fee saving on $136,500 is about $88 a year. In an IRA there is no tax on switching.
Yes, all hold the S&P 500 at index weights: 504 to 505 holdings in October 2026, because some companies have two share classes. Their 2022 returns were −18.1% to −18.2%.
Trailing 12-month distribution yields to Sep 30, 2026 were 1.10% for IVV, 1.06% VOO, 1.01% SPYM and 0.99% SPY (Exent market data). The gaps come from fees and payout timing; total return is what matters.
No. Like any index fund it aims to match the index before expenses, so it trails it slightly. VOO trailed the S&P 500 by 0.04 points a year over the 10 years to Sep 30, 2026, against about 0.15 for SPY, because its fee is lower.
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Educational content, not investment advice. Examples are illustrative; past performance does not guarantee future results.