SARON boom in German-speaking Switzerland: 32 percent market share, but why?

Moneypark's semi-annual study delivers one of the year's most striking figures. From January to June 2026, 32 percent of the mortgage volume brokered in German-speaking Switzerland was financed via SARON products; in Western Switzerland it was just 10 percent, a figure that has also dropped from 14 percent at the previous year's level. Across Switzerland as a whole, the SARON share is 24 percent. Historically, this quota hovered around 10 percent for a long time. For new purchases in German-speaking Switzerland, more than 40 percent of buyers are now opting for a variable interest rate. Where does this difference come from and what does it mean for the individual choice of mortgage?

The initial interest rate situation explains part of it

The SARON, the Compounded Swiss Average Rate Overnight, tracks the key interest rate set by the Swiss National Bank. The SNB lowered its key rate to 0 percent on June 19, 2025, and has kept it there without change as of June 18, 2026. The underlying SARON is slightly in negative territory, but banks do not pass this on negatively. Together with the margin of 0.7 to 0.9 percent, depending on the provider, this results in an effective interest rate for new customers of about 0.8 to 1.0 percent.

A ten-year fixed-rate mortgage today costs between 1.5 and 2.0 percent, depending on the provider. The premium compared to SARON is therefore about 80 to 120 basis points. Anyone who does not absolutely need the security of a long-term commitment saves considerably with a SARON mortgage, even if a moderate rise in interest rates is expected in the coming years.

Why German-speaking Switzerland is more likely to choose SARON

The marked difference between language regions is not explained by interest rate levels, which are the same for everyone, but by three structural factors.

Financial situation and reserves. In the urban economic areas of Zurich and Zug, the average capital resources of buyers are higher. Those who have reserves can sit out short-term interest fluctuations and are more willing to step onto the playing field of variable rates. In many regions of Western Switzerland, the proportion of first-time buyers with tight budgeting is higher.

Confidence in one's own financial situation. SARON requires a certain mental resilience, since the interest rate is adjusted in three-month steps. A household with stable dual income and a buffer in the budget takes an increase of 50 basis points more calmly than one whose affordability calculation is already scraping the five percent threshold.

Advisory practices of banks and brokers. Eastern Swiss and Zurich cantonal banks made SARON and its predecessor LIBOR socially acceptable at an early stage. In Romandy, many institutions traditionally stick to the image of the fixed-rate mortgage as the serious standard product for a longer period. This influence is still noticeable in advisory meetings today.

The ten-year fixed-rate mortgage remains the market leader

Despite the SARON boom, the ten-year fixed-rate mortgage remains the most popular product, with 38 percent of the volume. Very long maturities of eleven years or more have almost disappeared with only one percent market share, according to Moneypark the lowest value in years. The typical Swiss compromise therefore is: a ten-year fixation as an anchor, often supplemented by a SARON tranche for the remaining sum. This split is now the standard case for medium to large financings.

When SARON is really worthwhile today

The initial situation favors SARON, but it's not a free pass. Four criteria help in the assessment.

Interest rate difference and expected remaining term. With financing of CHF 800,000, choosing a ten-year fixed-rate mortgage at 1.8 percent compared to a SARON mortgage at 0.9 percent costs about 7,200 francs more in interest per year. Over ten years, this adds up to 72,000 francs, as long as the SARON rate remains constant. A rise in SARON of 100 basis points reduces this advantage by around 8,000 francs per year. For SARON to become more expensive than the fixed-rate mortgage over the full term, it would have to average significantly more than 90 basis points above today’s level.

Budget reserve for interest rate increase. Rule of thumb: The household should be able to cope with an increase in mortgage interest rates of 1.5 to 2.0 percentage points without restricting their standard of living. Those who do not have this reserve are buying their own predictability with a fixed-rate mortgage.

Time horizon and life stage. Those who intend to sell the property in the medium term or foresee a professional change gain additional flexibility with SARON. Exiting from a fixed-rate mortgage is expensive, as the discussion about prepayment penalties makes clear.

Interest rate expectations, not forecasts. No one knows the path of SARON in five years. Those who choose SARON are not doing so on the basis of a forecast, but on the basis of a risk decision: exchanging the short-term savings for the long-term uncertainty. This balance is personal and not a calculation a bank can lay out finished for their customer.

Who is better off staying with the fixed-rate mortgage

For some constellations, the fixed-rate mortgage remains the more sensible choice, despite SARON's interest rate advantage. First-time buyers with limited affordability, single-income households on a tight budget, and people nearing retirement usually find it easier with a stable interest rate. Even those who want to keep the property for the long term and value an easy-to-plan payment stream will find the ten-year fixation the right answer. The German Swiss SARON quota of 32 percent, conversely, means that 68 percent in this region still opt for fixed conditions.

Outlook for the second half of the year

The SNB is likely to keep the key interest rate unchanged until the next decision in September 2026. Capital market interest rates are moving in a narrow range, driven by the geopolitical situation. As long as the SNB does not signal that it will raise the key rate again, SARON remains the cheapest current mortgage on the market. When deciding today, the focus should be less on the interest rate advantage and more on your own willingness to live with a variable rate. That very willingness is the true reason for the 32 percent in German-speaking Switzerland and the 10 percent in Western Switzerland.

Sources:
MoneyPark and PriceHubble: Financing and Real Estate Update (FIMU) H1 2026, August 2026,
Moneypark Study H1 2026 via Finews