What Is a BVG Voluntary Buy-In (Einkauf)?
BVG is the Swiss law governing your occupational pension — often called Pillar 2, the second layer of Switzerland's three-pillar retirement system (Pillar 1 is the state pension, Pillar 3 is your private savings). A voluntary buy-in, or Einkauf in German, lets you make an extra contribution to close a gap in your pension fund. Gaps commonly appear because you spent years working abroad before moving to Switzerland, because your salary increased and your coverage didn't automatically catch up, or because you previously withdrew Pillar 2 funds to buy a home and never repaid them.
For Swiss residents generally, an Einkauf is one of the most efficient tax moves available: the contribution is deductible from taxable income in the year you make it, and the money grows inside the pension fund largely untaxed until retirement. This is exactly why Swiss financial advisors recommend it so readily — and exactly why, as a US citizen or green card holder, you need to pause before assuming it works the same way on your US return.
The Swiss Tax Benefit — And Why It's Real
On the Swiss side, there's no ambiguity. A voluntary buy-in reduces your cantonal, communal, and federal taxable income for that year, sometimes substantially, depending on your income bracket and the size of the gap you're closing. Cantons do apply some restrictions — for example, limits on withdrawing the buy-in as capital shortly after making it, which exist to prevent people from using the maneuver purely as a short-term tax play rather than genuine retirement savings. Within those rules, though, the Swiss deduction is straightforward and well understood by any local tax advisor.
Does the IRS See It the Same Way?
Here's where things get less tidy. The IRS does not automatically treat a Swiss Pillar 2 contribution as deductible simply because Switzerland does. US tax law starts from its own definitions of retirement plans and doesn't extend a courtesy deduction just because a foreign government offers one. This is precisely the kind of mismatch we cover in more depth in our guide to Swiss pension plans and US tax compliance, which walks through how each pillar is treated when your tax home spans two systems.
The relief valve most practitioners point to is Article 21 of the US-Switzerland tax treaty, which addresses the treatment of pension contributions and can support excluding a Swiss buy-in from US taxable income in certain circumstances. But 'can support' is the key phrase — this isn't a blanket exemption you get by default. Treaty positions typically require an affirmative claim on your return, and how convincingly that claim holds up depends on the specifics of your plan, your visa and residency history, and how the contribution was structured. This is a case where the phrase 'it depends on your situation' isn't a brush-off — it's the accurate answer, and it's why this deserves personal review rather than a general rule applied blindly.
Article 21 isn't a checkbox
Claiming treaty relief on a Swiss pension buy-in generally means taking a specific position on your return, not ticking a box that applies automatically to every American with a Pillar 2 account. Get the claim reviewed against your specific facts before you rely on it.
What You Must Track for Future Withdrawals
Even if a buy-in is handled cleanly in the year you make it, the story doesn't end there. Whatever portion of your Pillar 2 contributions the US did treat as coming from already-taxed dollars becomes your basis — the amount you can eventually receive back without being taxed on it again. If you don't track this over the years, you risk paying US tax a second time on money that was never a deduction to begin with when you finally take a lump sum or annuity in retirement. Our companion piece on Pillar 2 basis tracking for US expats goes through the mechanics of maintaining this record year over year.
- The amount and date of every voluntary buy-in you make, not just your regular mandatory contributions
- Which portion, if any, was treated as a US-taxable event versus excluded under a treaty position
- Your cumulative basis figure, updated annually rather than reconstructed years later from memory
- Any prior Pillar 2 withdrawal (for example, for a home purchase) that reduced your accrued benefit and therefore the size of the gap you're now buying back
- How the contribution interacts with your annual FBAR (Report of Foreign Bank and Financial Accounts) and FATCA (Foreign Account Tax Compliance Act) reporting for the pension account itself
When a Buy-In Intersects With a Home Purchase
Many Einkauf decisions come up alongside a home purchase — either because you're repaying a prior Pillar 2 withdrawal used for a down payment, or because you're weighing a buy-in against using pension funds directly for the purchase instead. Both paths carry separate US reporting consequences on top of the pension basis question, which is why it's worth reading them together rather than in isolation. Our guide to buying a home in Switzerland as a US citizen covers how mortgage structuring and Lex Koller rules interact with your US filings, and it's a natural companion to any buy-in decision timed around a property purchase.
The Practical Path Forward
None of this means a voluntary buy-in is off the table for Americans in Switzerland — plenty of people make this work well, and the Swiss tax savings can be meaningful. It means the decision needs two lenses instead of one: what your Swiss advisor sees as a smart, deductible move, and what that same contribution creates on your US return in the year you make it and in every year after, until you eventually draw on the pension. Getting the Article 21 position right, and starting your basis tracking from day one rather than reconstructing it a decade later, is the difference between a clean outcome and an expensive surprise. This is exactly the kind of cross-border question we help clients think through at US Expat Wealth, where both systems get looked at together rather than one at a time.
Don't assume the deduction transfers
A buy-in that saves you real money in Switzerland can still be fully taxable income in the US if the treaty position isn't properly established. Confirm the treatment before you count on the savings twice.