Pension Fund Buy-Ins: How Tax Savings, the Blocking Period and Withdrawal Interact
A voluntary buy-in into the pension fund is considered a classic tax-optimization move. But the mechanism behind it has more moving parts than the tax deduction alone suggests: marginal tax rate, a three-year blocking period, later taxation on withdrawal. How the pieces work together.
Anyone with a funding gap in their pension fund – for example after a salary increase, a career break, or a change of pension fund – may close it with voluntary payments. The Vorsorgeausweis (the annual pension-fund benefit statement) states the maximum possible amount. Such a buy-in is deductible from taxable income, and that is where its reputation as a tax-saving instrument comes from.
How the Tax Saving Arises
The buy-in reduces taxable income in the year of payment. How much that is worth is determined by the marginal tax rate: the higher the income and the steeper the progression in the canton of residence, the greater the effect of each franc paid in. That is why it is often suggested to stagger buy-ins over several years instead of making a single payment – progression is then broken multiple times. Whether and how strongly this works in an individual case depends on the specific income and tax situation in those years.
The Three-Year Blocking Period
The law sets a clear limit: after a buy-in, the resulting benefits may not be drawn as capital for three years (Art. 79b BVG) – the blocking period (Sperrfrist). Tax authorities take this seriously – a lump-sum withdrawal within the period can jeopardize the tax deduction retroactively. Anyone planning to draw all or part of their balance as capital at retirement must therefore time their last buy-ins early enough. An early withdrawal for home ownership (WEF) plays into the same mechanism.
Deferred, Not Eliminated
The buy-in does not eliminate the tax, it defers it. When the balance is later withdrawn, it is taxed again – as a pension, in full together with other income; as capital, once, at a reduced rate. The actual net effect of a buy-in is therefore the difference between today's saving and later taxation – and that depends on the canton, the form of withdrawal, and the timing. In between lies a second, often overlooked effect: the balance grows within the pension fund tax-free, without income or wealth tax on interest and balance.
Four Gears, One Timeline
Today's marginal tax rate, the blocking period, interest credited within the fund, taxation on withdrawal: each of these gears turns at a different point in life. Whether and when a buy-in pays off therefore does not show up in a single year's tax bill, but only over the course of the years leading up to retirement and beyond.
In Wealth4Life, buy-ins can be modeled as a scenario – as a single payment or staggered, combined with the planned form of withdrawal – with the tax consequences of every single year in the canton of residence. That turns the rule of thumb into a traceable calculation for your own situation.