Compare calendar, threshold and never approaches to rebalancing.
Explain why rebalancing means trimming winners and topping up laggards.
Weigh the tax and cost friction of rebalancing too often.
You built a portfolio with target weights — say a core of broad index funds and a few satellite positions you sized deliberately. Then the market did what markets do: some sleeves ran, others lagged, and the weights you chose on day one quietly drifted into weights you never chose. Rebalancing is how you decide whether to pull them back — and one of the most over-done activities in retail investing.
What rebalancing actually is
Rebalancing means returning your portfolio to its target weights. Nothing more exotic than that. If you decided on 70% core and 30% satellites, and a strong run pushed the satellites to 40%, rebalancing brings them back toward 30% — by selling some of what grew or by directing new contributions into what shrank.
Here is the part nobody enjoys hearing: rebalancing means trimming your winners and topping up your laggards. It feels backwards. The position that just made you money is the one you sell down; the one that disappointed you is the one you add to. That discomfort is not a bug — it is the entire mechanism. It is a rule that forces "sell high, buy low" on you precisely when your gut is screaming the opposite.
Why drift matters at all
Drift is risk creep. The 30% satellite sleeve you sized for a reason becomes 40%, then 45% — and your portfolio is now riskier than the one you actually signed up for, without you ever deciding to take that risk. Rebalancing is not about chasing returns. It is about keeping the risk you hold equal to the risk you chose. That is the whole point of going back to Module 3 on sizing.
The three approaches
There are exactly three honest answers to "when do I rebalance?" — and a beginner can do well with any of them, as long as the choice is deliberate rather than emotional.
Approach 1
Calendar-based
You rebalance on a fixed schedule — once a year is the common choice — and ignore the portfolio in between. Upside: simple, mechanical, no second-guessing. Downside: the calendar does not know what the market did. You might rebalance when almost nothing has drifted (pure friction) or stay hands-off through a wild swing because your date has not arrived yet.
Approach 2
Threshold-based
You rebalance only when a sleeve drifts past a band — for example ±5 percentage points from its target. Upside: you act when there is something to act on, and ignore noise. Downside: it requires checking, and a wide band means you tolerate more drift between trades. The band is the dial: tight bands trade more, wide bands trade less.
Approach 3
Never / lazy
You let it ride and rebalance only with new contributions — steering fresh money toward whatever is underweight, never selling. Upside: zero selling means zero realised tax, minimal cost, and it suits a small portfolio that is still growing by deposits. Downside: once the portfolio is large relative to your contributions, new money can no longer move the weights enough, and drift wins.
The honest default
A hybrid
Most disciplined investors land on check on a calendar, act on a threshold: look once or twice a year, but only trade if something has actually drifted past your band. The calendar controls how often you look; the threshold controls whether you touch anything. Drift is the signal — the calendar is just the reminder to check for it.
The trap: drift is the signal, not the calendar alone
A date on its own tells you nothing. If you rebalance every January regardless of whether anything moved, you generate trades — and therefore costs and taxes — for no risk-management benefit. The calendar should prompt you to check; the drift past your band is what justifies a trade. Mechanically trading the calendar is how good intentions turn into needless friction.
The friction: why more is not better
Every rebalancing trade costs you something, and in Germany the tax side is the bigger bite. Selling a position that has gained realises a profit — and a realised profit is a taxable event. Remember the Abgeltungsteuer lesson: gains are taxed at roughly 25% plus Soli (and church tax where it applies), once you are past the annual Sparerpauschbetrag. Rebalance too eagerly and you pull tax forward that you could have left compounding inside the position for years.
1
Spread, not just commission
Even where a broker charges no commission, you still cross the bid-ask spread on every buy and sell. Small per trade, real when you do it often across many positions.
2
Realised tax drags compounding
A euro paid to the Finanzamt this year is a euro that stops compounding. Frequent rebalancing converts unrealised gains into a tax bill you did not have to trigger yet.
3
Contributions first
Where you can, rebalance by directing new money at the underweight sleeve instead of selling the overweight one. No sale means no realised gain, no tax event — the cheapest rebalance there is.
A note on tax — this is education, not tax advice
Numbers here illustrate the mechanism only, and German tax rules change. The point is directional: selling winners has a tax cost in a taxable account, and that cost is a reason to rebalance less often, not more. For your own situation, a Steuerberater is the right call — this lesson just teaches you why the question matters.
Tying it back to core and satellite
Rebalancing is where the core/satellite structure earns its keep. Your core is meant to be boring and broad — it drifts slowly and rarely needs a hand. Your satellites are the volatile, deliberately small sleeves — and they are exactly where a band gets breached, because they move most. A satellite that doubled is not a victory to protect; it is a position now twice the size you decided it should be. Trimming it back to target is you honouring the sizing decision your calmer, pre-purchase self already made.
Try first
You are 28, still contributing €300 every month, and your portfolio is around €6,000. One satellite has drifted about 4 points over target. Should you sell to rebalance right now?
The takeaway
Rebalancing keeps your risk equal to the risk you chose — by selling winners and topping up laggards, which will always feel wrong and is supposed to. Pick one rule and hold to it: calendar, threshold, or contributions-only. Let drift past a band be the thing that triggers a trade — not the calendar by itself, and never a hunch. And in a German taxable account, lean toward doing it less, because every sale is a tax event you chose to trigger early.
Check yourself
Check yourself
1.What does rebalancing a portfolio actually mean?
2.Why is rebalancing emotionally hard, and why is that difficulty considered the point rather than a flaw?
3.In a German taxable account, what's the main reason to lean toward rebalancing less often rather than more?
4.Your target is 70/30 core/satellite with a ±5 point threshold. Satellites have drifted to 33%. Using a 'check on calendar, act on threshold' rule, what should you do?