An ETF rotation strategy keeps a portfolio invested in whichever ETFs are strongest right now, and rotates out of them when they weaken. Because ETFs cover whole sectors, regions or asset classes, rotation lets you apply one set of rules to several parts of the market.
How ETF rotation works
You start with a fixed list of ETFs. On a regular schedule, you score each one, usually by recent performance, and hold the top few. When a holding drops out of the top group, it is sold and replaced.
Common ETF rotation universes
| Universe | Example holdings | What it rotates between |
|---|---|---|
| Sector rotation | Technology, health care, energy, financials sector ETFs | Parts of the stock market |
| Asset class rotation | US stocks, international stocks, bonds, gold, real estate | Different types of assets |
| Risk-on / risk-off | A stock index ETF and a bond or cash-like ETF | Being invested or defensive |
Building a basic rotation strategy
- Pick the universe. Choose liquid ETFs that are genuinely different from each other.
- Choose a ranking rule. Total return over 3 to 12 months is the most common.
- Decide how many to hold. Holding the top one is aggressive; the top two or three spreads risk.
- Add a defensive rule. For example, hold a bond or cash-like ETF instead of any pick whose own trend is negative.
- Set the schedule. Monthly rebalancing is a common balance between responsiveness and cost.
Mistakes to avoid
- Too many look-alike ETFs. Several funds tracking almost the same index add complexity, not diversification.
- Ignoring leveraged ETF decay. Leveraged and inverse ETFs reset daily, so over longer periods their returns can differ sharply from the stated multiple of the index.
- Short test periods. Many ETFs are relatively young. Test on the longest history you can, and be cautious about results that rely on a single bull market.
- Forgetting costs and taxes. Rotation creates turnover, which matters in taxable accounts.
Scoring methods beyond simple return
Total return over a fixed lookback is the most common way to rank ETFs, but it is not the only one. Some traders blend several lookbacks, such as one, three and six months, so the ranking reacts to new leadership without depending on one setting. Others adjust returns for volatility, so a steady riser can outrank a fund that got to the same place with large swings. A third approach scores each ETF by how far it trades above its own long-term moving average. Whichever method you choose, keep it simple enough that you can explain why it should work, and test a few close variations rather than only the best one.
Ranking by recent performance is a form of relative strength ranking, and the whole approach is a close cousin of the momentum trading strategy. The difference is mainly the universe: rotation works with a short list of broad ETFs instead of hundreds of individual stocks.
How many ETFs to hold
Holding only the single top-ranked ETF gives the purest exposure to the strongest area, but it also means the portfolio can swing sharply and change completely at each rebalance. Holding two or three reduces dependence on a single pick when their exposures differ. Compare the combined result and the overlap between the funds. With larger universes, holding the top quarter or top third is a common middle ground.
Defensive rules for falling markets
In a broad sell-off, every stock ETF can fall together. A rotation strategy that must always hold the top stock funds will simply hold the ones falling least. Defensive rules help:
- Absolute trend check. Only hold an ETF if its own trend is positive, such as trading above its 200-day average.
- Defensive slot. Include a short-term Treasury or cash-like ETF in the universe so it can be selected when everything else weakens.
- Partial defense. Move only part of the portfolio to the defensive asset when some, but not all, holdings fail the trend check.
Note that bonds do not always protect. In 2022, many stock and bond ETFs fell at the same time, which is a good reason to test defensive rules across several different bear markets.
Using leveraged and inverse ETFs in rotation
Some rotation strategies add leveraged S&P 500 ETFs for stronger exposure in uptrends, or inverse S&P 500 ETFs to profit in downtrends. Because these funds reset daily, they can behave very differently from their stated multiple over longer holding periods. If you include them, test them separately, size them conservatively and define and test the exit rules before adding them to the lineup.
Testing a rotation strategy
Run the test across the longest history you can, include trading costs, and look at how results change with the number of holdings, the lookback and the rebalance schedule. Keep the final test period separate from the work of choosing those settings. Look for sensible behavior across nearby choices.
Build an ETF rotation strategy in Portfolio Boss
PB can rank a list of ETFs and select the top qualifying funds within one strategy. The Ranking Panel combines weighted rules, while buy and sell filters control eligibility and exits. Its machine learning can search for those rules together, saving you the work of guessing every setting.
You can also build separate strategies for individual ETFs. Strategy Mill automates that research across a list, then filters the candidates for review. Ranking ETFs inside one strategy and combining several strategies are two different jobs, and PB supports both.
Portfolio Boss founder Dan Murphy began trading in 1997. His aim is to turn research into a process clients can follow with less effort. Autonomous Portfolio Management (APM) handles the trading through Interactive Brokers. In Co-Pilot mode, you review the prepared orders and press Transmit; full automation handles transmission for you.
Put your next idea to the test, free
Build your first ETF strategy and see how the rules behave before expanding the lineup. Portfolio Boss Evo is 100% free for life for the first 100,000 signups ($1,999 value). Download now. Advanced modules are paid.
Backtested and hypothetical results have limitations and do not guarantee future results.
