Backtested and hypothetical results, shown for educational purposes only — not investment advice. Past performance does not indicate future results.

Mean Reversion

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US indices SPY QQQ IWM DIA International FXI EEM
ZENA’s daily moves don’t reliably mean-revert. The dip-buy stats below are weak or noisy — at the daily close-to-close horizon this signal works cleanly on the broad equity indices (SPY, QQQ) and mostly breaks down on commodities and crypto.
Expected return · next day

— Stretched, weak edge$0.87 · 2026-10-30

ZENA follows through on the prior day (trends) at the daily horizon.

Current stretch: RSI(2) at 8 is deep oversold, -1.7σ below the 50-day average — but the daily edge here is thin.

Today
-5.5%
last close-to-close
RSI(2)
7.8
oversold
vs 50-day avg
-36.5%
-1.7σ
Streak
1 down
closes in a row
Off 20-day high
-37.6%
pullback depth
Reversal character: after an up day, next day averages +0.71% (40% up); after a down day, -0.11% (43% up). Reversal score -0.82%, 1-day autocorrelation 0.149— positive = trending.
Growth of $1, close-to-close, since 2024. The two lines are held the day after their trigger and sit in cash otherwise, so they trade a similar number of days — the comparison is the dip-buy leg (green) against its opposite (red), not against buy & hold. No costs or slippage.
Forward return by RSI(2) at the close (toggle mean / median above). Low RSI(2) = short-term oversold. Bar outlined = where is now.
Forward return by how far price sits from its 50-day average (in standard deviations). Outlined = now.
The next-day return after a run of consecutive up or down closes. A rising staircase toward the “down” end is mean reversion.
Mean-reversion edge by year — the dip-buy leg's next-day return minus its opposite (after a down day vs after an up day, or bottom- vs top-decile RSI(2)). Above zero = the name faded moves that year. Bars are the mean, which a crash can swing hard in either direction (2020); the tick marks are the median — the typical day.
Matched-exposure comparisons — each pair trades a similar number of days, so raw returns are comparable. RSI(2) deciles use thresholds ≤4.8 and ≥88.5.
RuleDays heldAvg / dayWin rate TotalCAGRSharpeMax DD
■ After a DOWN close 293 (56%) -0.106% 43.0% -71% -45.3% -0.16 -76.3%
■ After an UP close 216 (41%) +0.714% 39.8% -44% -24.5% 0.37 -85.9%
■ Bottom 10% RSI(2) 53 (10%) -0.939% 45.3% -57% -33.2% -0.43 -72.1%
■ Top 10% RSI(2) 53 (10%) +5.147% 37.7% +178% +63.6% 0.69 -61.1%
How to read this  ▾

Some assets mean-revert at short horizons (a sharp move tends to partly reverse); others trend (a move tends to continue). At the daily close-to-close horizon the reversal shows up cleanly and consistently in the broad equity indices and mostly breaks down elsewhere — commodities, crypto, and individual stocks carry their own momentum. The names above are the ones where it holds up.

RSI(2) is a 2-day momentum oscillator — below ~10 is short-term oversold, above ~90 overbought. Distance from the 50-day average is measured in standard deviations (z-score). Streak counts consecutive up or down closes. For each, we show what happened over the next 1–5 days, historically.

The strategy table pairs each dip-buy rule against its opposite — day-after-a-down-close vs day-after-an-up-close, and the bottom vs top RSI(2) decile. Both legs of a pair are held one day and trade a similar number of days, so raw returns compare fairly (unlike buy & hold, which wins on total return simply by always being invested). Avg / day — mean return on the days the rule is in the market — is the cleanest apples-to-apples number. Frictionless: no commissions or slippage. A character test, not a tradeable system. Past behaviour is not a forecast.

End-of-day adjusted closes, refreshed nightly. 523 trading days, 2024-10-01 – 2026-10-30. Backward-looking statistics, not investment advice.