# Dual momentum bot: run Antonacci’s GEM automatically > Run Gary Antonacci’s dual momentum rules as a bot: SPY, VEU or AGG, checked once a month. See the backtest, then run it on paper or with Alpaca. Written by [Tactfolio research team](https://tactfolio.com/about/editorial-policy.md), published 2026-10-16, updated 2026-10-16, data as of 2026-09-25. A dual momentum bot runs Gary Antonacci's Global Equities Momentum (GEM) rules for you. Once a month it holds one fund: US stocks, stocks outside the US, or bonds. On Tactfolio you can read every rule, check the backtest, and run it on paper or in your own Alpaca account. ## Key points - The bot checks once a month and holds one of SPY, VEU or AGG. - It holds stocks only while US stocks have beaten Treasury bills over 12 months. - It usually switches only a few times a year. - Its worst backtest loss came in the fast 2020 crash, about a third. - You run your own copy, and you choose the balance it trades. ## What does the dual momentum bot do? The dual momentum bot follows two tests from Antonacci's 2014 book *Dual Momentum Investing*. Momentum means assets that have risen lately tend to keep rising for a while. - **Absolute momentum:** have US stocks (SPY) beaten Treasury bills (BIL) over the past 12 months? If not, hold US bonds (AGG). - **Relative momentum:** if they have, hold whichever did better over 12 months, US stocks (SPY) or stocks outside the US (VEU). Each 12-month return is measured from month-end closes, as the book does. The full rules, sources and yearly results are in the [dual momentum strategy guide](https://tactfolio.com/strategies/dual-momentum.md). ## How did dual momentum do in the backtest? These figures come from the strategy's article and were measured on prices through September 25, 2026. - Over the ETF era, from August 2008, it returned less than the S&P 500 with a smaller worst drawdown. A drawdown is how far a portfolio falls from its last high point. - From early August 2008 to the end of that year it gained about 5%, while the S&P 500 lost more than a quarter. - It was fully in stocks in the February and March 2020 crash. It lost about a third and took until early 2021 to recover. - In 2022 it lost 17%, almost as much as the S&P 500. These results are hypothetical, from past prices after trading costs. They are not a track record. [How to read a backtest](https://tactfolio.com/docs/concepts/reading-a-backtest.md) explains each number. ## How to run the dual momentum bot on Tactfolio Five steps take you from the rules to a running bot. 1. **Open the live strategy.** Open the [live dual momentum strategy](https://tactfolio.com/s/tactfolio/antonacci-gem) to see its rules and its daily-updated backtest. 2. **Copy it to your account.** Sign up for free and copy it. Your copy is yours to change. 3. **Change it if you want.** In the [builder](https://tactfolio.com/builder), try a shorter lookback, a different bond fund, or Treasury bills as the safe asset. The backtest reruns as you edit. 4. **Run it on paper.** In Trade, a paper account runs the bot with pretend money at real market prices and emails you a summary after each close. 5. **Connect Alpaca when you are ready.** Use your own Alpaca account, paper or live, with your own API keys. The bot trades only the starting balance you give it. ## When does the dual momentum bot struggle? - **Sudden crashes.** A 12-month signal checked once a month cannot react to a fall that happens within weeks. - **Falling bonds.** When stocks and bonds fall together, the bond fallback does not protect you. - **Leadership changes.** When US and foreign stocks trade places often, it can switch late each time. ## Common questions ### How often does the dual momentum bot trade? It checks at each month end and trades only when the winning fund changes. That usually happens only a few times a year. ### What ETFs does the dual momentum bot use? It holds SPY for US stocks, VEU for stocks outside the US, and AGG for US bonds. It compares against BIL, a Treasury bill fund, for the absolute momentum test. ### Can I change the dual momentum rules? Yes. Copy the strategy and change the lookback, the funds or the safe asset. You can also look at [Accelerating Dual Momentum](https://tactfolio.com/strategies/accelerating-dual-momentum.md), which uses shorter lookbacks. ### Does dual momentum still work? Since the book came out in late 2014 it has made money but trailed the S&P 500. Its sharpest loss came in 2020. The live record on the strategy page shows how it is doing now. ## The ideas behind this bot - [Momentum strategy](https://tactfolio.com/learn/momentum-strategy.md): A momentum strategy buys recent winners by a written rule. - [Tactical asset allocation](https://tactfolio.com/learn/tactical-asset-allocation.md): What tactical asset allocation is, how it differs from strategic allocation, and what Faber's model did in 2008 and after, with dated backtest figures. - [Backtest a portfolio](https://tactfolio.com/trading-tools/backtest-portfolio.md): Backtest a portfolio of US stocks and ETFs. Enter tickers and shares, pick when to rebalance, and get the results with a link to share. - [SPY: State Street SPDR S&P 500 ETF Trust](https://tactfolio.com/etf/spy.md): What SPY holds, its 0.0945% yearly fee, returns by year, its worst drop, and which Tactfolio strategies hold it. - [VEU: Vanguard FTSE All-World ex-US ETF](https://tactfolio.com/etf/veu.md): What VEU holds, its 0.04% yearly fee, returns by year, its worst drop, and which Tactfolio strategies hold it. - [AGG: iShares Core U.S. Aggregate Bond ETF](https://tactfolio.com/etf/agg.md): What AGG holds, its 0.03% yearly fee, returns by year, its worst drop, and which Tactfolio strategies hold it. ## Sources - [Risk Premia Harvesting Through Dual Momentum (2012)](https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2042750), Gary Antonacci, SSRN, accessed 2026-10-16 - [Paper Trading](https://docs.alpaca.markets/docs/trading/paper-trading/), Alpaca, accessed 2026-10-16