SNB Assessment of December 11, 2025: Impact on SARON, Fixed-Rate Mortgages and Your Interest Rate Strategy

Overview: SNB keeps key interest rate at 0% – what this means for mortgages

The Swiss National Bank (SNB) left its policy rate unchanged at 0% at its monetary policy assessment on December 11, 2025. This signals continuity – in an environment where observed inflation recently fell back to 0.0% (November) and the conditional inflation forecast (at constant key rate) of 0.2% for 2025, 0.3% for 2026 and 0.6% for 2027 clearly remains within the corridor of price stability. For mortgage borrowers and property buyers, this means short-term stability in money market rates and still muted expectations for medium and long-term rates – although not without risks from the global economy and potential market disruptions.

Source: Swiss National Bank, press release on monetary policy assessment of 11.12.2025.

SNB Interest Rate Tools: Fine-Tuning with Signaling Effect

• Key interest rate: 0.0% (unchanged)
• Remuneration of sight deposits: up to the limit at the SNB policy rate; above that with a discount of 0.25 percentage points (as of today, implicitly –0.25%).
• Foreign exchange market: Willingness to intervene remains in place to prevent inappropriate appreciation of the franc.

The message for the mortgage market is clear: The money market is expected to remain close to 0%. The remuneration above the sight deposit limit with a discount can slightly push short-term market rates (SARON) down at times. In practice, however, many banks apply contractual minimums (“floor”) for SARON mortgages, so negative base rates are not or only partially passed on to clients.

Inflation: Low, Anchored – and Guiding for Interest Rate Markets

The SNB points to a decline in inflation from 0.2% (August) to 0.0% (November). Drivers were especially lower price trends in hotels, rents, and clothing. The conditional inflation forecast remains low throughout the forecast horizon and is within the range of price stability. This is central to mortgage interest rates:

• Low, credibly anchored inflation reduces pressure on long-term interest rates and the CHF swap curve (2/5/10 years), which fixed-rate mortgages are based on.
• With a constant monetary policy, the forecasts point to a moderate, non-inflationary environment – a plus for predictable financing costs.

At the same time: International yields and risk premiums influence CHF swaps and mortgage bond yields. A purely domestic view thus falls short.

Economy: Switzerland solid, but not immune

• Global economy: Growth in Q3 was stronger worldwide than expected. In the US, inflation remained elevated, in the eurozone it approached the target.
• Base scenario: Moderate global growth.
• Risks: Trade policy uncertainty (tariffs, new barriers) could dampen momentum. At the same time, upside potential exists if the global economy surprises positively.
• Switzerland: GDP declined in Q3, primarily due to special effects in the pharmaceutical sector (anticipated US deliveries). Other industries and services saw slight growth. Unemployment has recently risen and is expected to increase further.
• SNB GDP forecast: 2025 just +1.5%, 2026 around +1%.

For mortgage borrowers, this means: Switzerland remains relatively robust, but the labor market is becoming somewhat cloudier. Income security and liquidity reserves therefore remain central in property financing.

Direct Impact on Mortgage Rates

SARON mortgage: short-term stability, with minor volatility risk

• Expectation: With the SNB key rate unchanged, SARON is likely to remain near 0% in the short term. Low fluctuations are possible, e.g. due to liquidity factors, sight deposit tiering and seasonal effects.
• Practice: Mortgage rate = SARON (daily/monthly rolling) + individual margin + possible floor. Check contractual minimums; a floor can prevent negative SARON values from reducing your interest payments.
• Budgeting: Stable payments are plausible. Still: Allow for a buffer for possible SNB adjustments or temporary market tensions.

Fixed-rate mortgage: muted medium/long rates – choose timing with discipline

• Foundation: Low inflation outlooks tend to argue for subdued swap rates and therefore more moderate rates for 5–10 year fixed-rate mortgages.
• But: International yields, mortgage bond spreads and bank margins can move rates – even without an SNB move. Geopolitical risks or new trade barriers could increase volatility.
• Opportunity: The current environment creates the chance to fix part of the financing at attractive conditions without having to go "all-in".

Interest Rate Strategy 2025/2026: How to Structure Your Mortgage

• Laddering maturities: Distribute the financing into several tranches (e.g. SARON, 3 years, 7 years). Advantage: Interest rate change risks are smoothed; refinancing dates are spread out.
• Clear hedging rules: Define in advance at which market levels you will partially lock in (e.g. if 5-year swaps exceed a defined threshold). This reduces decision stress in volatile times.
• Use SARON with discipline: Consider a "banded" or "capped" mortgage if you want to combine variable flexibility with a ceiling. Pay attention to costs and conditions.
• Weigh forward options: If a renewal is due in 6–18 months, a forward fixed-rate mortgage can provide planning certainty. Compare the forward premium to your risk benefit.
• Optimize amortization mix: Combine direct vs. indirect amortization (pillar 3a/insurance solution) depending on your tax and liquidity situation. The goal remains to reduce the loan-to-value to 65% in the medium term (amortization of the 2nd mortgage within the standard period according to bank requirements).

Affordability, Loan-to-Value and Liquidity: Banks Remain Strict – and Rightly So

• Affordability: Even with low market interest rates, banks use stress test rates that are well above the current level. Check if interest rate shocks, rising ancillary costs and amortization can still be supported by your household finances.
• Loan-to-value: Standard is a maximum loan-to-value of 80% of market value; the 2nd mortgage usually has to be amortized within 15 years or by retirement. Higher equity reduces interest costs and increases room for negotiation.
• Sources of equity: At least a part (e.g. 10% of the purchase price) must come from free funds and may not come from pillar 2 assets. Plan carefully if using/pledging pension fund assets – consider effects on pension and taxes.
• Reserves: Conservatively budget 0.5–1.0% of the property value per year for maintenance and incidental costs. Additionally, a liquidity reserve for income losses or unexpected investments is recommended.

Scenarios 2026/2027: Base, Downside and Upside Paths

• Base scenario: Key interest rate remains near 0%, inflation remains low. SARON mortgages remain affordable; fixed-rate mortgages move within a moderate corridor. Laddering and partial fixed rates remain sensible.
• Downside scenario (weaker world economy, new trade barriers): Economy cools, unemployment rises, risk aversion increases. Long-term rates could fall, but spreads might rise. Strategy: Stay flexible, stagger refinancing, keep additional liquidity buffers.
• Upside scenario (positive growth surprise): Yields rise worldwide; fixed-rate mortgages become more expensive. Strategy: Those with high interest rate risk sensitivity (high debt, tight affordability) secure part of the loan amount long-term at an early stage.

Buy-to-let and Income Properties: Calculate with Caution

• Rental income: Recently weak rent inflation has dampened overall inflation. Budget conservatively for only small nominal rent increases and pay attention to the mechanism of the reference interest rate for rents.
• Interest coverage ratio: Check the debt service coverage ratio (DSCR). Even at low interest rates, net rent after costs (including maintenance, vacancies, management) should comfortably cover interest and amortization.
• Vacancy and location risk: Micro-location, supply/construction activity, and demand determine income sustainability more than the current interest rate.
• External financing: For income properties, banks often require more conservative approaches (e.g., lower maximum allowable loan-to-value, stricter affordability criteria). Plan with safety margins.

Currency Environment: Strength of the Franc Remains a Double-Edged Sword

The SNB maintains the option to intervene in the foreign exchange market. The franc tends to appreciate in times of global tension. For mortgage borrowers with foreign currency income (e.g. cross-border commuters) or with assets in foreign currencies this means:

• Actively manage currency risks (natural hedges, aligning maturities and currencies of cash flows, consider hedging solutions if needed).
• Do not base property purchases on short-term FX opinions; stabilize cash flows in CHF whenever possible.

What to Watch Now – Your Practical Monitoring Plan

• SNB assessments and conditional inflation forecast: Key for the direction of monetary policy.
• Swiss economic data: GDP trend after pharma-induced decline, development of unemployment.
• International interest rates and trade policy: US tariffs, new barriers and geopolitical risks affect fixed-rate mortgages via yields and spreads.
• CHF swap curve (2/5/10 years) and mortgage bond yields: Direct drivers of fixed mortgage rates.
• Bank margins and product terms: Margins, floors, band options, prepayment penalties, forward premiums.

Concrete Tips for Your Financing

• Checklist approach:
• Define financing mix: Set ratio of SARON vs. fixed-rate mortgage, according to planning certainty and risk tolerance.
• Test affordability with stress test: Internally calculate using clearly higher interest rates than are currently paid in the market.
• Stagger maturities: Do not concentrate all maturities on one date.
• Read contract details: Floors, adjustment periods (e.g. monthly SARON calculation), margin review, switching rights between tranches.
• Use forward sensibly: Only bring forward as much as suits your planning horizon – forward costs.
• Optimize equity structure: Only use pillar 2/3a with respect to pension and tax consequences; ensure 10% of equity comes from free funds.
• Budget for maintenance and investments: A realistic CAPEX plan increases bank acceptance and prevents liquidity shortages.
• For renewers (refinancing in <18 months):
• Obtain quotes early and monitor swap levels.
• Consider partial fixing in tranches instead of "all or nothing".
• For SARON tranches, define a clear exit or cap plan.
• For first-time buyers:
• Include purchase price and ancillary costs (transfer of ownership, notary, fees) in your calculation.
• Test affordability even under pessimistic assumptions (income shock, interest rate increase, higher maintenance).
• Do not use up pillar 3a/reserves entirely for equity – keep an emergency buffer.

Conclusion: Use Stability with a Sense of Proportion

The SNB is keeping its key interest rate at 0% and confirming an environment of very low, anchored inflation. In the short term, this points to stable SARON rates and subdued medium to long-term interest rates. However, external risks – especially trade policy tensions – remain a potential driver of volatility for fixed-rate mortgages via global yield markets.

For mortgage borrowers, this means: Use the stability, but don't be careless. Stagger maturities, define clear hedging rules, keep liquidity reserves high and consistently test affordability under stress. Anyone who plans carefully can secure solid financing conditions in this environment – and at the same time remain flexible enough to respond appropriately to surprises.

Note: This article is based on the SNB press release of 11.12.2025 and supplements it with practical financing perspectives. It does not replace individual advice; conditions and credit approvals always depend on your personal situation and the bank's individual criteria.