Privatier — sell or box?

Funding life from the portfolio: sell shares each year, or draw on a rolling box line and square up at the end?

€
€
Tune assumptions
20y
6.5%
40%
With offset on, the accumulated box loss nets against the portfolio gain at horizon. Click Roll a market for a random sequence of annual returns (μ ≈ expected return, σ = 16 %).
Withdrawal rate · 4.00%
Box rate (12m EUR) · 2.54%
Offset on — Path B gains +€66,351
A · Sell
€1,296,924
Portfolio left
€1,660,252
Tax during drawdown
€172,921
Cost basis left
€282,705
B · Box line
€1,767,317
Portfolio at horizon
€3,523,645
Tax at liquidation
−€771,111
Box debt at payoff
−€1,051,568
Both paths fund 20 years × €40,000 of spending. Path B defers the entire tax load to horizon and lets the portfolio compound undisturbed — strongest when after-tax portfolio return exceeds the box rate.

How the comparison works

A · Sell

Sell shares year by year. The unrealized-gain ratio sets the tax drag per EUR sold — cost basis updates proportionally. Risk: too high a withdrawal rate empties the portfolio before horizon.

B · Box line

Draw annually against a rolling box-spread line. Portfolio stays fully invested, compounding tax-deferred. At horizon repay the box in one shot and pay tax on the remaining gain — the full tax load shifts from today's pile to the N-years-later pile.