Average path, by market
Upper panel: cumulative return since the September close, averaged over ten Octobers (line) with the range between the 25th and 75th percentile of the years (band). Lower panel: the average return of each trading day.
S&P 500SPY
Nasdaq 100QQQ
Euro Stoxx 50EZU
DAX 40EWG
FTSE MIBEWI
FTSE 100EWU
Australia 50EWA
Market = equal-weighted daily return of the current constituents. Trading days 22 and 23 exist only in some years, so the charts stop at the last day present in at least eight of the ten Octobers; the table uses the full month.
In numbers
| Market | October, average | Days 1–10 | Days 11–end | Best average day | Worst average day |
|---|---|---|---|---|---|
| S&P 500SPY | +1.22% | +0.52% | +0.70% | day 12 (+0.45%) | day 18 (-0.58%) |
| Nasdaq 100QQQ | +0.90% | +0.37% | +0.53% | day 3 (+0.68%) | day 18 (-0.81%) |
| Euro Stoxx 50EZU | +0.67% | +0.22% | +0.45% | day 12 (+0.52%) | day 20 (-0.46%) |
| DAX 40EWG | -0.30% | +0.15% | -0.46% | day 17 (+0.48%) | day 15 (-0.62%) |
| FTSE MIBEWI | +0.22% | -0.26% | +0.47% | day 12 (+0.73%) | day 20 (-0.53%) |
| FTSE 100EWU | -0.41% | -0.18% | -0.23% | day 12 (+0.44%) | day 8 (-0.43%) |
| Australia 50EWA | +0.19% | +1.00% | -0.82% | day 12 (+0.52%) | day 19 (-0.45%) |
Averages of the ten yearly paths. Best and worst day = trading day with the highest and lowest average return.
How to read this
Method. For each market and each October, the daily returns of the constituents (adjusted prices, local currency) are averaged with equal weight, and compounded from the first to the last trading day. Trading days are numbered within each month, so weekends and holidays do not shift the calendar.
Limits. Ten Octobers is a small sample, and individual days rest on ten observations: a single large move (such as the October 2018 sell-off or the 2022 rebound) can dominate a day's average. Among 21 daily averages per market, a few will look striking by chance. Members are the current constituents taken back in time, so the history carries survivorship bias. These are research notes, not recommendations.
Research material only — not personalized financial advice. Past performance does not predict future results. Contact: domderrico@gmail.com.