One of These S&P 500 Funds Has Trailed for 10 Years. Its Fans Say That’s the Point.
Two S&P 500 funds hold nearly identical stocks, yet their returns have drifted so far apart over a decade that the gap itself tells a story about what most investors misunderstand about diversification.
Two funds hold nearly identical rosters of large American companies drawn from the same S&P benchmark. The only meaningful difference between SPDR Portfolio S&P 500 ETF (NYSEARCA:SPYM) and Invesco S&P 500 Equal Weight ETF (NYSEARCA:RSP) is how much of each name they own. That single choice has produced a decade of divergent returns, and the very reason SPYM won is why its owners should look closely at what they hold.
Scoreboard as of September 23, 2026
SPYM last traded at $91.12, and RSP at $212.70, both delayed intraday marks pulled on Wednesday morning. Both funds have a full decade of price history on record, so every window below is a clean, like-for-like comparison.
| Window | SPYM | RSP |
|---|---|---|
| 1 month | +1.37% | −3.69% |
| Year to date | +14.49% | +12.36% |
| 1 year | +17.43% | +14.64% |
| 5 years | +87.37% | +50.52% |
| 10 years | +322.64% | +202.99% |
SPYM leads across every window, and the separation widens over longer horizons. The one-month column shows the gap still opening in real time.
Why the Cap-Weighted Fund Won
SPYM weights each S&P 500 constituent by market capitalization, so the biggest companies drive the bulk of returns. The N-PORT filing dated June 30, 2026, shows Apple alone at 6.59% of net assets, worth roughly $10.1 billion inside a fund carrying $153.9 billion in total net assets. Amazon added 3.62%, Alphabet’s two share classes combined for more, and Broadcom at 2.77%.
That is the whole story of the past decade. A handful of mega-cap technology and platform businesses grew faster than everything else, and a cap-weighted vehicle automatically fed more capital into the winners. It is also an uncomfortable truth for anyone using SPYM as a broad-market anchor: this fund is a concentrated bet on a very short list of names, dressed as diversification.
What RSP Is Built to Do
RSP tracks the S&P 500 Equal Weight Index, holding every constituent at roughly the same weight and rebalancing quarterly. Apple carries the same weight as the 400th name in the index. The construction deliberately underweights mega-cap tech and tilts toward industrials, financials, materials, and real estate. In a decade led by the largest platforms, that design was always going to trail.
RSP also throws off cash. It paid a $0.7951 distribution on September 21, 2026, its 93rd quarterly payment on record, and its trailing 12-month distributions totaled $3.18. Total return closes some of the price gap, though the one-month reading suggests the divergence is still widening.
Verdict
A long-horizon investor who wants the S&P 500 as it actually exists today—cap-weighted, concentrated at the top, and technology-heavy—will lean toward SPYM. Its decade of leadership is a direct product of that structure. The investor who wants meaningful exposure to the other 490 companies and can accept long stretches of trailing the headline index will favor RSP.
What could flip the calculus is a durable rotation away from mega-cap leadership. Until that shows up in the numbers, SPYM keeps winning and RSP keeps being exactly what its fans wanted: the more diversified of the two.
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Trey has been an editor and author at 24/7 Wall St. for more than a decade, where he has published thousands of articles analyzing corporate earnings, dividend stocks, short interest, insider buying, private equity, and market trends. His comprehensive coverage spans the full spectrum of financial markets, from blue-chip stalwarts to emerging growth companies.
Beyond 24/7 Wall St., Trey has created and edited financial content for Benzinga and AOL's BloggingStocks, contributing additional hundreds of articles to the investment community.
Trey's editorial expertise extends across multiple publishing environments. He served as production editor at Dearborn Financial Publishing and development editor at Kaplan, where he helped shape financial education materials. Earlier in his career, he worked as a writer-producer at SVE. His freelance editing portfolio includes work for prestigious clients such as Sage Publications, Rand McNally, the Institute for Supply Management, the American Library Association, Eggplant Literary Productions, and Spiegel.
Outside of financial journalism, Trey writes fiction and has been an active member of the writing community for years, moderating workshop sessions at regional conventions.
