Tool · Simulator
Asset allocation, rebalanced.
Drift, year by year
target60/40·25 yr→ 83/17
Target portfolio
60%
Stays at the mix you chose. You sleep at night.
Drift portfolio
83.2%
Bought stocks once, never touched it again.
The gap
+23.2 pp
Extra equity exposure you did not sign up for.
Target stocks· What you signed up for
drift· Where it ends up if you never rebalance
stress test
If stocks crash 40 % at the end
Target portfolio loses
−24.0%
Drift portfolio loses
−33.3%
extra loss from drift
+9.3 pp
60%
10%100%
25
540
Deterministic projection. Stocks 7 %/yr, bonds 2 %/yr, no inflation. Drift = no rebalancing ever; target = rebalanced once a year. Real markets bounce around these averages, but the direction of the drift is the same.
From Lesson 18
Allocation & rebalancing
This simulator closes a longer lesson on allocation: three classic mixes (cautious, balanced, aggressive), why portfolios drift, and three rebalancing strategies (calendar, threshold, contributions). Read the lesson for the why, then come back here for the what-if.
Read the full lesson →