Calendar rebalancing

Calendar rebalancing is a disciplined approach of returning a portfolio’s asset-class weights to target allocations on a fixed schedule — quarterly, semi-annually, or annually — regardless of how much the allocations have drifted from target.

How calendar rebalancing works

An investor commits to rebalancing on a fixed schedule, such as:

• Quarterly. Every three months, return the portfolio to its target allocation.
• Annually. Once per year (often at year-start or year-end), rebalance.
• Semi-annually. Twice per year.

On the rebalancing date, regardless of current market conditions or how far the portfolio has drifted, the investor:

1. Calculates current weights.
2. Identifies which assets are over-/underweight relative to target.
3. Sells overweight assets and buys underweight assets to restore targets.

Advantages

1. Simplicity. The rule is straightforward: rebalance on date X every year/quarter.
2. Automation. Calendar schedules can be automated, removing decision-making.
3. Discipline. A fixed schedule enforces rebalancing even when it feels wrong (selling winners in bull markets, buying losers in crashes).
4. Psychological anchoring. The known schedule helps investors commit to the discipline.

Disadvantages

1. Inefficient timing. A drift that occurs on Day 1 of a quarter is rebalanced on Day 90 (end of quarter), missing 90 days of drift.
2. Costly in trending markets. In a long bull market, calendar rebalancing keeps trimming stocks (the winner) to buy bonds (the loser). You miss the bulk of the rally.
3. Tax inefficiency. Annual rebalancing on a fixed date can trigger capital gains even when the drift is minimal.
4. Inflexibility. If market conditions change drastically mid-quarter (e.g., a crash), calendar rebalancing does not respond until the next rebalancing date.

Typical schedule

Annual rebalancing is most common among individual investors, often done at year-start or year-end:

• Year-start rebalancing. Done in January after the new year (after bonuses, 401k contributions, and new year motivation).
• Year-end rebalancing. Done in December before taxes or before the following year.
• Tax-loss harvesting integration. Many investors combine calendar rebalancing with tax-loss harvesting to rebalance and harvest losses simultaneously.

See also