The largest stocks keep outrunning the average S&P 500 stock
Equal weight (RSP) is 30% below its 2015 peak relative to cap weight (SPY), and has been at or below this level on 0.1% of days since 2004. Over 12 months RSP trailed SPY by 4.5 points, and since 2004 it compounded 10.0% a year against 10.8% for SPY.
Equal weight relative to cap weight (RSP / SPY)
Index, January 2004 = 100, weekly
Both series are total return (dividends reinvested), so the ratio compares like with like.
Rolling 12-month return gap
RSP 12-month total return minus SPY 12-month total return, percentage points, weekly
What it means · inference
- Index returns lean increasingly on the largest members
- A setback in a few giants moves SPY most
- Most of the drop from the peak came since 2023
For investors · general, not personal financial advice
- Cap-weighted exposure concentrates risk in a handful of names
- Equal and cap weight carry different concentration risks
What would change it
- A sustained rise of the 12-month gap above zero
- A mega-cap sell-off lifting the ratio without broader gains
Method
- What is measured: Ratio of the equal-weight S&P 500 ETF (RSP) to the cap-weight S&P 500 ETF (SPY), dividend-adjusted, indexed to 100 in January 2004, through 30 Sep 2026. A falling line means the largest companies are outrunning the average one.
- Ratio of dividend-adjusted closes; indexed to 100 on the first trading day of 2004 and sampled at Friday closes for the chart.
- 12-month gap = difference of trailing 252-session total returns. Compound annual returns use the first and last closes in the window.
- ETF prices only; no single-name data, so the reader-safe universe does not enter this exhibit.
Sources
- MCH research warehouse, daily dividend-adjusted ETF closes (Alpha Vantage); through 30 Sep 2026.
Universe
| Names in the published feed | 886 |
| Excluded: held, suspended, withdrawn, deferred, deal-pending or pending review | 54 |
| Reader-safe universe | 832 |
| Used in this exhibit | 0 |
Names whose rating is held, suspended, withdrawn, deferred or under a pending deal are excluded from every exhibit, so no held output appears here.
General and impersonal investment research. Not personal financial advice. Forecasts, valuations and model outputs are estimates and may be wrong. See Investment Disclaimer.
MCH Analysis is a general investment-research publication of MCH Advisory (Pty) Ltd. It is not personal financial advice and does not take your circumstances into account. MCH is not a licensed financial services provider or a registered investment adviser. Past performance, whether actual or simulated, does not predict future results. Subscriber Agreement | Privacy and Cookie Notice | Research Governance Policies