Wealthy PotFXAIX vs SPYM (Formerly SPLG): A 0.015% Fund or a 0.02% ETF for the S&P 500
FXAIX and SPYM both track the S&P 500 at very low cost. FXAIX is Fidelity's index mutual fund at 0.015% a year; SPYM is State Street's S&P 500 ETF at 0.02%. SPYM is the fund many investors still know as SPLG: the ticker changed on 31 October 2025 and nothing else about the fund did. The two hold the same companies; 99.8% of FXAIX's money sits in companies SPYM also owns. The fee gap is $0.50 a year on $10,000, too small to matter. So the choice is about how you buy: FXAIX prices once a day, takes any dollar amount and is most at home in a Fidelity account; SPYM trades all day at any broker, at about $91 a share.
Table of Contents
The Short Answer
- Same stocks. 99.8% of FXAIX's weight was in companies SPYM holds, and 99.2% of SPYM's in companies FXAIX holds. The overlap tool reads 94.5% only because the two holdings reports are a month apart.
- Fees: FXAIX 0.015%, SPYM 0.02%. $1.50 against $2.00 a year on $10,000; $5 a year on $100,000.
- Both stay close to the index. Over five years FXAIX trailed the S&P 500 by 0.01 points a year (to 30 September 2026) and SPYM by 0.03 to 0.04 (to 31 August and 30 June 2026). No common date is published yet for a head-to-head table.
- SPLG is now SPYM. Same fund, same strategy, new name and ticker from 31 October 2025.
- FXAIX: mutual fund, no purchase minimum, one price a day. SPYM: ETF, about $90.56 a share (NAV, 2 October 2026), trades all day.
- Do not hold both. Pick by account: FXAIX at Fidelity or in a 401(k) that offers it, SPYM at almost any other broker.
SPYM Is the Old SPLG
State Street's filing announced that "Effective October 31, 2025," the SPDR Portfolio S&P 500 ETF's "exchange ticker symbol will change," from SPLG to SPYM. The fund's name also became State Street SPDR Portfolio S&P 500 ETF. Its annual report says the change "did not result in any changes to the Fund's Investment Objective, Principal Investment Strategies or Principal Risks." If you owned SPLG, you now own SPYM; if you search for SPLG, SPYM is the fund you will find.
One historical detail matters for the return figures. SPYM did not always track the S&P 500. It followed the Russell 1000 until 15 November 2017, an SSGA large-cap index until 23 January 2020, and the S&P 500 from 24 January 2020. Its one-, three- and five-year records are pure S&P 500; its ten-year record is not.
Same Index, Same Stocks
FXAIX normally invests "at least 80% of assets in common stocks included in the S&P 500® Index." SPYM seeks to track the S&P 500 and uses "a sampling strategy, which means that the Fund is not required to purchase all of the securities represented in the Index." In practice it held 506 positions on 1 October 2026, against 503 in the index, so the sampling is close to full.
Our Portfolio Overlap Checker puts the overlap at 94.5%, across 495 shared companies. It adds up the smaller of the two weights for every company both funds hold, using each fund's SEC holdings report (Form N-PORT): Fidelity's dated 31 May 2026 and State Street's dated 30 June 2026. Prices moved in that month, and the tool counts each drift as non-overlap.
| Largest shared holdings | % of FXAIX (31 May 2026) | % of SPYM (30 Jun 2026) |
|---|---|---|
| NVIDIA | 7.89% | 7.51% |
| Apple | 7.05% | 6.58% |
| Alphabet | 6.11% | 5.83% |
| Microsoft | 5.14% | 4.29% |
| Amazon | 4.07% | 3.62% |
| Micron | 1.68% | 2.02% |
The date-free test is the one to trust: 99.8% of FXAIX's weight sat in companies SPYM also held. These are the same portfolio.
FXAIX vs SPYM Side by Side
| FXAIX | SPYM (formerly SPLG) | |
|---|---|---|
| Full name | Fidelity 500 Index Fund | State Street SPDR Portfolio S&P 500 ETF |
| Index | S&P 500 | S&P 500 (since 24 Jan 2020) |
| Expense ratio | 0.015% | 0.02% |
| Prospectus cost example, $10,000 over 10 years | $19 | $26 |
| Type | Open-end mutual fund | Exchange-traded fund |
| How you buy | At the day's closing NAV, in dollar amounts | On NYSE Arca during market hours, at market prices |
| Minimum | None, per the prospectus | One share, about $90.56 at NAV (2 Oct 2026), unless your broker sells fractions |
| Holdings | 507 (28 Feb 2026) | 506 (1 Oct 2026) |
| Ten largest companies | 40.6% (31 May 2026) | 37.9% (30 Jun 2026) |
| Size | $749.4 billion (28 Feb 2026) | $177.3 billion (2 Oct 2026) |
| Portfolio turnover | 3% | 3% |
| Securities lending | Yes | Yes, up to 40% of net assets |
| Dividends paid | April, July, October, December | Quarterly |
| Inception | 17 Feb 1988 | 8 Nov 2005 |
Returns: Both Track the Index Closely
We could not put these two in one return table. Fidelity has published FXAIX's returns to 30 September 2026; State Street's page still showed 31 August (month end) and 30 June (quarter end) when we checked on 5 October. SPYM's current prospectus stops at 31 December 2024. Subtracting returns from different dates would mislead you, so the table below compares each fund with its own index on its own date. For two funds following the same index, how closely each tracks it is the comparison that counts.
| Average annual return | As of | 1 year | 3 years | 5 years |
|---|---|---|---|---|
| FXAIX | 30 Sep 2026 | 15.72% | 22.87% | 13.78% |
| S&P 500 | 30 Sep 2026 | 15.74 | 22.89 | 13.79 |
| FXAIX behind index | 0.02 | 0.02 | 0.01 | |
| SPYM (NAV) | 31 Aug 2026 | 20.34% | 21.00% | 12.76% |
| SPYM's benchmark | 31 Aug 2026 | 20.38 | 21.04 | 12.79 |
| SPYM behind index | 0.04 | 0.04 | 0.03 | |
| SPYM (NAV) | 30 Jun 2026 | 22.28% | 20.58% | 13.37% |
| S&P 500 | 30 Jun 2026 | 22.32 | 20.61 | 13.41 |
| SPYM behind index | 0.04 | 0.03 | 0.04 |
What this shows. FXAIX gave up about a hundredth or two of a point a year to the index; SPYM about three or four hundredths. The fee gap is half a hundredth, so most of SPYM's small extra shortfall comes from something other than the fee. Neither issuer breaks it down, and we do not guess. The prospectuses tell the same story over longer periods: to 31 December 2025, FXAIX returned 14.81% a year over ten years against 14.82% for the index.
In dollars, it is small. A shortfall gap of two to three hundredths of a point is $2 to $3 a year per $10,000. It is a reason to prefer FXAIX if you are at Fidelity anyway, not a reason to move brokers.
Ten-year figures. SPYM reports 15.36% a year over ten years to 31 August 2026, but part of that decade it tracked other large-company indexes, so we do not set it against FXAIX's S&P 500 record.
This is educational information, not personalized investment advice. Past performance does not guarantee future results, and all investing carries the risk of loss.
Which One Fits You
You have a Fidelity account or IRA: FXAIX. Slightly lower fee, slightly closer tracking, no minimum, any dollar amount, and dividends reinvest automatically unless you choose otherwise.
Your 401(k) offers FXAIX: use it. A 401(k) can only offer what is on its menu, and SPYM would be reachable only through a brokerage window if your plan has one.
You use any other broker: SPYM. FXAIX's prospectus warns "you may be charged a transaction fee if you buy or sell shares through a non-Fidelity broker." An ETF can be held almost anywhere, and SPYM's share price of about $91 makes it easy to buy in whole shares even without fractional trading.
You want to trade during the day, or use limit orders: SPYM. FXAIX fills once a day at the 4 p.m. Eastern close, and Fidelity blocks new purchases for 85 days if you make "two or more roundtrip transactions in a single fund within a rolling 90-day period."
Taxable account: in FXAIX vs IVV, an ETF's smaller ten-year tax drag offset its higher fee and the after-tax figures came out level. We found no same-date after-tax figures for SPYM and FXAIX, so we draw no conclusion for this pair. If you already hold either with gains, do not sell to switch.
Other options. SPYM against State Street's older and pricier SPY is in SPY vs SPYM, and against Vanguard's VOO in SPYM vs VOO. FXAIX against Vanguard's ETF is in FXAIX vs VOO.
Sources & Methodology
- Fidelity 500 Index Fund Summary Prospectus, 29 April 2026: the 0.015% fee table, strategy, no purchase minimum and returns to 31 December 2025.
- Fidelity Concord Street Trust, Form 485BPOS filed 24 April 2026: NAV timing, the roundtrip rule, non-Fidelity broker fees and the distribution schedule.
- Fidelity Concord Street Trust, Form N-CSR for the year ended 28 February 2026: FXAIX's size, holdings count and turnover.
- Fidelity's FXAIX performance page: returns to 30 September 2026.
- SPYM Summary Prospectus, revised 3 February 2026: the 0.02% fee table, sampling strategy, turnover and index history.
- SPDR Series Trust supplement dated 21 October 2025: the SPLG to SPYM ticker change.
- SPDR Series Trust, Form 485BPOS filed 24 October 2025: securities-lending limit.
- SPDR Series Trust, Form N-CSR for the year ended 30 June 2026: SPYM's returns, assets, holdings and the renaming statement.
- State Street's SPYM page: assets and NAV on 2 October 2026, holdings on 1 October 2026, and returns to 31 August 2026.
- FXAIX Form N-PORT for 31 May 2026 and SPYM Form N-PORT for 30 June 2026: the holdings behind the overlap and top-ten figures.
How the overlap was computed. The Portfolio Overlap Checker sums the smaller of the two weights for each company held by both funds, using each fund's latest N-PORT in our dataset. The two filings are a month apart; we state both dates rather than adjust either one.
What we could not verify. A head-to-head return table on one date (none was published when we checked). Bid-ask spreads and trading volume for SPYM. Which non-Fidelity brokers carry FXAIX, and which 401(k) plans offer either fund.
This article is for general education and is not investment, tax or legal advice. Past performance does not guarantee future results, and all investing carries the risk of loss. Figures were checked against the sources above on 5 October 2026; verify current figures with each fund company before acting.
FAQ: FXAIX vs SPYM
Is SPYM the same as SPLG?
Yes. SPLG's ticker changed to SPYM on 31 October 2025, along with the fund's name. State Street says the change did not alter the fund's objective, strategy or risks.
Is FXAIX the same as SPYM?
Same index, different wrapper. Both hold the S&P 500. FXAIX is a Fidelity mutual fund priced once a day; SPYM is a State Street ETF that trades all day.
Which is cheaper, FXAIX or SPYM?
FXAIX, at 0.015% against 0.02%. On $100,000 that is $15 against $20 a year.
Which has performed better?
There is no same-date comparison yet. Each tracked the S&P 500 closely: over five years FXAIX trailed it by 0.01 points a year and SPYM by 0.03 to 0.04, on their latest published dates.
What does SPYM cost to buy?
One share, about $90.56 at NAV on 2 October 2026, unless your broker sells fractional shares. FXAIX has no minimum.
Should I hold both FXAIX and SPYM?
No. They hold the same companies. Owning both adds a second line to track and nothing else.
Which is better for a Roth IRA?
At Fidelity, FXAIX. At any other broker, SPYM. Inside a Roth, taxes on distributions do not matter, so cost and convenience decide.
Cite This Page
Journalists, educators and bloggers are welcome to cite this comparison. Please link back so readers can reach the underlying filings.
"FXAIX vs SPYM (Formerly SPLG): A 0.015% Fund or a 0.02% ETF for the S&P 500." Wealthy Pot, 2026. https://wealthypot.com/fxaix-vs-spym/
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