RSP_GSPC_BREADTH
Market breadth — equal-weight S&P 500 vs cap-weighted, normalized
Latest value
1.4344
as of 2026-05-01
All-time percentile
31th
1-year change
-5.4%
Time series
Showing 628 of 1,256 data points
About this series
The ratio of the Invesco S&P 500 Equal Weight ETF (RSP) to the S&P 500 cap-weighted index (^GSPC), normalized to 1.0 at the earliest shared date. A rising ratio means equal-weight is outperforming cap-weight — the rally is broad. A falling ratio means cap-weight is outperforming — the rally is narrow, driven by a few mega-caps.
Why it matters: When a handful of mega-cap stocks drive the index, the "market" looks healthy but underlying breadth can be weakening. Historically, narrow rallies (falling RSP/SPX ratio) have preceded corrections more often than broad rallies. Tracking this ratio gives a breadth reading that's much cleaner than arbitrary technical indicators.
How to read it: Watch the direction and slope, not the absolute level. A multi-month decline in this ratio during a rally in SPX is a warning — the participation is narrowing. A multi-month rise means breadth is improving (usually healthy). The current deep decline in this ratio is one of the most extreme concentration readings on record.
Caveats: Only available since RSP's 2003 inception. The ratio is normalized to 1.0 at that start date, so absolute levels across long time spans include the accumulated out/underperformance — which is informative but means "1.0" isn't a magic number.