Sector Relative Strength (RS vs SPY)
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Definition
How a sector is performing relative to the broad market (SPY) — a ratio that reveals leadership and lag independent of whether the overall market is up or down.
How to read it
Relative strength is the sector's price divided by the benchmark's; a rising RS line means the sector is outperforming (leading), a falling line means underperforming (lagging), regardless of absolute direction. Leadership tends to persist, so rising RS is a tailwind for longs within that sector and falling RS a headwind. RS is a comparison, not a valuation — a leading sector can still fall in a down market, just less than SPY.
How practitioners use it
Used as context among multiple indicators — never as a standalone signal to act.
Less common professional uses
RS-line breakouts frequently lead absolute-price breakouts — a sector making a relative high before a price high is an early leadership tell. Intra-sector rotation timing: the RS baton often passes from high-beta sub-industries to defensives late in a move; track sub-industry RS, not just the sector ETF, to catch the handoff. RS divergence at index highs (fewer sectors with rising RS) is a breadth-of-leadership warning that a cap-weighted benchmark masks.
Sources & provenance
Sector ETF prices vs. SPY benchmark; Educational framework; not investment advice
This page is educational content published by Pachira Aquatica Global LLC. It is not investment advice and not a recommendation.