The Swiss affordability rules in five minutes — with a worked example.
Banks calculate conservatively: an imputed rate of 5 % (not the current mortgage rate), incidental costs of 1 % of the purchase price per year, plus amortisation of the second mortgage. These housing costs may amount to at most one third of the gross income.
At least 20 % of the purchase price as equity, of which at least 10 % must be "hard" equity from outside the pension fund (savings, securities, pillar 3a).
Purchase price CHF 1'000'000: mortgage CHF 800'000 → imputed interest CHF 40'000, incidental costs CHF 10'000, amortisation ≈ CHF 10'000. Total CHF 60'000 of annual costs → required gross income ≈ CHF 180'000. Equity: CHF 200'000, of which CHF 100'000 from outside the pension fund.
With a new build there are often one to two years between reservation and payment — time enough to organise the equity and compare offers. Whoever looks at the financing only when the listing appears decides under time pressure. Our advisor works through your situation without obligation.