Market timing vs plan: a calm rule from “A Random Walk”
Published: 2026-05-26
When markets wobble, “maybe I should get out and come back later” feels like prudence. Most of the time it’s just market timing in nicer clothes. Here’s a calm rule that keeps your decisions boring — and boring is often what works.
A short quote worth remembering
In A Random Walk Down Wall Street, Burton G. Malkiel famously joked that a “blindfolded monkey throwing darts” could pick stocks as well as experts. (Paraphrased excerpt; used here as a reminder: forecasts are not a plan.)
The rule: don’t trade forecasts — trade your written plan
If you don’t have a plan written down, every scary headline becomes a new “strategy.” So the rule is simple:
- You’re allowed to change your portfolio only for reasons your plan already lists.
- If the reason is “I think the market will do X next month,” you don’t trade it. You log it and do nothing.
What a beginner plan can be (in 6 lines)
- Goal & horizon: e.g., long-term (10+ years)
- Core allocation: e.g., 80% global stocks, 20% bonds (UCITS ETFs)
- Contribution rule: invest monthly, regardless of news
- Rebalancing rule: rebalance when allocation drifts by, say, 5 percentage points
- When you’re allowed to de-risk: only when horizon shortens or your ability/need to take risk changes
- Emergency rule: never invest emergency cash
Two practical “anti-timing” moves that still feel active
- Use contributions: if you’re anxious, keep investing smaller but consistent amounts (don’t go to zero).
- Rebalance (don’t speculate): if stocks fell and your plan says 80/20, rebalancing is a disciplined buy — not a prediction.
The takeaway
If you feel an urge to time the market, the best fix is rarely a smarter forecast. It’s a simpler plan and a rule that forces you to follow it.