Buy-and-Hold vs. Rebalancing

A buy-and-hold strategy means you set an initial asset allocation and leave it untouched. A rebalancing strategy means you periodically restore your portfolio to its target weights. The trade-off between the two—whether drift increases returns by riding winners, or increases hidden risk—has no single answer. It depends on market regime, tax efficiency, costs, and your personal discipline.

The case for letting winners run

When you buy-and-hold without rebalancing, your best performers grow larger. A diversified portfolio that starts 60% equities and 40% bonds may gradually shift to 75% equities as stock markets appreciate. This is sometimes called “accidental momentum” or “letting winners run.”

In bull markets, this works beautifully. Equities outpace bonds, so your drift toward higher equity exposure amplifies gains. You sidestep transaction costs and taxes that rebalancing would trigger. Over long periods—particularly the multi-decade bull markets of the 1980s and 2010s—many buy-and-hold portfolios handily outperformed rebalanced versions, purely because they rode the equity wave further.

The emotional case is equally potent. Rebalancing forces you to sell winners and buy losers—a deeply uncomfortable feeling. Buy-and-hold eliminates that friction entirely. You simply wait.

The hidden risk in drift

Yet drift is not free. Your portfolio becomes increasingly concentrated in whatever asset class has performed best. If equities have just rallied hard and now comprise 75% of your portfolio, you’ve inadvertently taken on substantially more equity risk than you intended.

This matters because risk tolerance and capacity are not static. You began with a 60/40 portfolio because you had a specific time horizon, income needs, and psychological comfort zone. A 75/25 portfolio is a different beast. In the next sharp downturn—the kind that hits every 7 to 10 years—you now face much larger drawdowns. A 30% equity crash translates to a 22.5% loss in your 75/25 portfolio versus a 18% loss in your original 60/40. That spread widens if the downturn is deeper.

Many investors, faced with 25% or 30% portfolio losses, panic and sell near the bottom—precisely when buy-and-hold discipline fails. A rebalanced portfolio, having forced you to sell equities at inflated valuations and own more bonds, now gives you dry powder to buy equities cheaply. It feels harsh at the time. It also tends to improve outcomes in recovery.

The transaction-cost question

The strongest counterargument to rebalancing is simple: it costs money. Every rebalance incurs bid-ask spreads, potential commissions (though commissions have largely vanished for equities), and market impact if you’re moving large sums. For a small retail portfolio with low rebalancing frequency, these costs are trivial—a few basis points at most. For a large institutional portfolio or frequent rebalancing, they compound.

Worse, rebalancing in taxable accounts crystallizes capital gains. If you’ve held an equity position for five years and it’s up 80%, rebalancing to cut it back triggers a large tax bill. That tax is a real cost, and it’s front-loaded—you pay it now, even if the rebalanced allocation performs better in the long run.

This is why many advisors recommend rebalancing only in tax-deferred accounts and using new contributions to rebalance taxable portfolios instead. A 60-year-old with $2 million split equally in a 401(k) and a taxable brokerage can rebalance the 401(k) annually without friction, then use dividends and new contributions to nudge the taxable account back toward its target over time.

When drift is actually performance drag

Paradoxically, rebalancing can improve returns by trimming what has performed best—but only if those winners are overvalued.

Imagine 2019: equities had soared for a decade, yielding a lopsided 80/20 portfolio that had abandoned its 60/40 target. Rebalancing in late 2019 meant selling equities and buying bonds. Six weeks later, the COVID crash arrived. The rebalanced portfolio’s larger bond allocation cushioned the fall, and the cash from bonds redeployed into equities at the bottom. The buy-and-hold 80/20 portfolio cratered harder and missed the recovery bounce because all capital was already in equities.

This is not reliable. Rebalancing only adds value if the asset class you’re trimming is genuinely expensive, and the one you’re buying is genuinely cheap. In a trending market (which equities were in 2014–2019), rebalancing can feel like fighting the tape.

The empirical middle ground

Long-run academic studies suggest that rebalancing has been a modest drag on returns in equities-dominated periods (like 1985–2020) and a modest boost in volatile, choppy markets. The difference is often smaller than the combined impact of expense ratios and taxes.

More important than the rebalancing choice itself is consistency. A disciplined buy-and-hold investor who stays the course through drawdowns tends to beat a rebalancer who gets spooked and abandons the plan. Conversely, a rebalancer who actually executes the plan tends to beat a buy-and-holder who panic-sells after years of drift into a concentrated, risky portfolio.

The strongest argument for rebalancing is not raw return, but risk control. It keeps your portfolio aligned with your actual tolerance and circumstances. It removes the need to guess whether an asset class is “overbought.” And it enforces a mechanical discipline: sell high, buy low, repeat.

A practical path

Many sophisticated investors split the difference:

• Use rebalancing bands to avoid constant trading (rebalance only if equities drift 5 or 10 percentage points from target).
• Rebalance tax-advantaged accounts without friction, and taxable accounts passively via contributions and dividends.
• Harvest tax losses when rebalancing triggers sales, offsetting the capital gains.
• Accept that some drift in a long bull market is normal and probably okay for patient investors with stable circumstances.

The choice is not between two equally optimal strategies. It’s between the systematic, low-stress discipline of rebalancing (which controls hidden risk and emotion) and the simplicity of buy-and-hold (which avoids costs and cuts through decisional complexity). Both can work. What matters is choosing one, understanding its trade-offs, and sticking with it.

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