What is Mean Reversion?
Mean reversion is a trading strategy based on the tendency of prices to return to their average after extreme movements. If an instrument deviates too far upward, it will likely correct. If too far downward, it will likely rise.
This strategy pairs perfectly with sentiment data — because extreme positioning IS an extreme deviation from the normal state.
Measuring "Too Far"
Bollinger Bands
20 SMA +/- 2 standard deviations. Price touching the upper band = statistically "overbought." Lower band = "oversold."
RSI
Measures whether an instrument is overbought (>70) or oversold (<30) relative to its own recent price movements. RSI extremes often correlate with sentiment extremes.
Sentiment as Mean Reversion Indicator
Each instrument has a "normal" positioning range on Sentmo (e.g., US30: 55-62% long). When positioning deviates significantly, the probability of reversion increases.
The Process
When Mean Reversion Fails
In strong trends, instruments can stay "overbought" for months. Use ADX as filter: ADX > 25 = trending market (avoid mean reversion). ADX < 20 = ranging market (ideal). News-driven moves create new equilibriums where the old average is irrelevant.
The Triple Confirmation Setup
Price at Bollinger Band extreme + RSI above 70 or below 30 + Sentiment extreme on Sentmo (>70% on one side). This triple confirmation produces the highest-probability mean reversion trades.