SteadyTapeQuantitative Market Research

RSI Breadth Oversold

67 spikes since 2005: SPY higher a month later 70% of the time against 67% for any day, with the month's low a median 2.0% below the spike.

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The share of stocks with RSI(14) below 30, measured on the 535-name basket back to 2006, and what SPY and QQQ did after that share spiked. The circulating chart draws lines from every spike to the index and calls it a bottoming phase; this measures it, with the spike threshold set as a percentile of the series and two fixed levels shown beside it. Reports the forward return against the unconditional base rate, how much further the index fell in the month after the spike, and how often a second spike followed within a month. Today's constituents only.

Oversold share
10.4%
percentile 94 · line 12%
Last spike
131 sessions ago
2026-03-12
SPY 1M after spike
70%
any day 67% · n=67
Further fall, median
-2.0%
any day -1.5%
Second spike within 1M
55%

When to run this study

Run during a selloff when the "percent of stocks oversold" chart is doing the rounds. It says how the index has behaved after the share of names with RSI(14) under 30 spiked, how much further it typically fell first, and how often the first spike was followed by another within a month. Context for sizing a dip buy, not a trigger.

Historical results

After a spike in the oversold share, against any day (2005–2026, 534 names)

ConditionIndexNFurther fall1W1W win1M1M win3M3M winSecond spike
Any daySPY5397-1.530.40601.56674.0474
Any dayQQQ5397-1.950.56591.84664.9374
Spike >= 12% (top 5%)SPY67-1.991.10663.60705.457255
Spike >= 12% (top 5%)QQQ67-2.951.02663.94696.577255
Fixed >= 20% of basketSPY33-2.800.91611.63675.977642
Fixed >= 20% of basketQQQ33-3.381.63671.59616.607342
Fixed >= 30% of basketSPY18-2.771.05722.37726.037239
Fixed >= 30% of basketQQQ18-4.340.84722.39616.277239