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Momentum · month-end rule · Indexes & ETFs

Dual Momentum on S&P 500 ETF

What the play says

In since Jun 30, 2023at $426.00SPY since then +82.6%

Latest reading: This stock 15.7% · S&P 500 (SPY) 15.7% · T-bills 3.7%

Next move

Stays in unless a month-end close lands below $700.12.

$700.12
−10.0% from the Oct 13 close of $778.01

Next check: this month's close, Oct 30, 2026

See every reason, for and against, in the Theory tester

SPY with the play, last two years

SPYPlay inPlay out

Shading shows the play's call from the close that triggered it.

12-month returns

This stockS&P 500 (SPY)T-bills

Dashed line at 0.

Growth of $10,000 since 2005

Dual MomentumBuy & hold

Log scale. After trading costs, with T-bill interest while out.

The record

The play against buying and holding SPY over exactly the same dates, after costs.

Play, since 2005Hold, since 2005Play, 5 yrsHold, 5 yrs
Annual return+9.7%+11.1%+12.7%+13.9%
Total return+649%+872%+81%+91%
Worst drawdown−33.7%−55.2%−18.8%−24.5%
Volatility14.5%18.9%13.7%17.1%
Sharpe ratio0.590.560.660.62
Time invested83%100%
Switches per year0.60

Every call, graded

Right on 6 of 14 closed calls (43%). In calls averaged +23.3%; out calls saw SPY move +5.3% on average.

CalledCallPriceUntilSPY movedResult
Jun 30, 2023IN$426.00now+82.6%open
Apr 29, 2022OUT$387.90Jun 30, 2023+9.8%✕ wrong
May 29, 2020IN$278.33Apr 29, 2022+39.4%✓ right
Mar 31, 2020OUT$235.74May 29, 2020+18.1%✕ wrong
Feb 28, 2019IN$248.68Mar 31, 2020−5.2%✕ wrong
Dec 31, 2018OUT$223.02Feb 28, 2019+11.5%✕ wrong
Mar 31, 2016IN$173.73Dec 31, 2018+28.4%✓ right
Jan 29, 2016OUT$162.91Mar 31, 2016+6.6%✕ wrong
Oct 30, 2015IN$173.83Jan 29, 2016−6.3%✕ wrong
Sep 30, 2015OUT$160.20Oct 30, 2015+8.5%✕ wrong
Jun 29, 2012IN$106.49Sep 30, 2015+50.4%✓ right
May 31, 2012OUT$102.33Jun 29, 2012+4.1%✕ wrong

An in call is right when the price rose before the next call; an out call is right when it fell. The latest 12 of 15 calls shown.

How the play works

  1. In at month-end when the stock's 12-month return beats both T-bills and SPY.
  2. Out otherwise.

Antonacci applies dual momentum to whole asset classes, not single stocks, and holds bonds when out.

On SPY itself only the T-bill test applies.

The case against

Valeriy Zakamulin tested moving-average timing on up to 155 years of U.S. stock data and found no statistically significant edge in the second half of that record. The rules earned their keep in a few severe bear markets and lagged buy and hold for long stretches in between.

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