Direct vs. Indirect Amortisation — The Pillar 3a Strategy Many Buyers Miss

The intuitive move: "we have a mortgage, we should pay it down." In Switzerland, the tax system quietly argues with that intuition — and offers a structure where you repay the bank without repaying the mortgage. Many buyers never hear about it until after they've signed.

The obligation both routes satisfy

The mortgage above two-thirds of the property value (the "second tranche") must be amortised within ~15 years or by retirement. How you amortise it is the choice:

Direct: you pay the bank, the mortgage shrinks, interest costs fall each year.

Indirect: the mortgage stays unchanged. Your amortisation payments go into a Pillar 3a account pledged to the bank; at the agreed date (or at retirement/sale), the accumulated 3a capital repays the tranche in one step.

Why indirect often wins the arithmetic

Three Swiss tax facts stack in its favour:

1. Mortgage interest is deductible from taxable income. Direct amortisation shrinks that deduction each year; indirect keeps it constant.
2. 3a contributions are deductible too — so the same franc that amortises indirectly also reduces taxable income (within the CHF 7,258 annual limit).
3. The eventual 3a payout is taxed at the reduced capital-payment rate, not as income.

At a 30%+ marginal rate — routine for the professionals reading this — the double deduction is material, year after year. The trade-offs, honestly stated: you keep paying interest on the full tranche (the deduction softens but doesn't erase it), the pledged 3a is spoken for, and if the 3a is invested, its value moves with markets — which is a return opportunity across 15 years and a sequence risk near the repayment date.

When each route fits

Indirect tends to win with high marginal tax rates, an unused 3a allowance (this fills it with money you had to pay anyway), long horizons, and comfort holding an invested 3a. Direct tends to win with lower tax rates, an allowance already maxed for other goals, a strong preference for falling debt, or an interest rate environment that shifts the equation. It's arithmetic, not ideology — and worth redoing when rates or tax rates change materially.

One structural note: the pledge covers the mandatory amortisation. Voluntary extra repayment of the first tranche is a separate decision — effectively a risk-free "return" equal to your after-tax mortgage rate, to be compared against what the money would earn invested. That's a portfolio question wearing a mortgage costume.

What are you optimising for?

Total after-tax wealth at the horizon, or the felt security of falling debt? Both are legitimate objectives; they just point at different routes. What isn't legitimate is defaulting into direct amortisation because nobody showed you the comparison.

Control questions: If you own — which route are you on, and was it calculated or defaulted? If you're buying — have you asked the bank for both quotes side by side, after tax? And is the 3a used for the pledge invested in line with its repayment date?