Polish Banks Begin WIBOR-to-POLSTR Switch; Mortgage Holders Face Rate Benchmark Change
Poland's banking sector is transitioning away from the WIBOR benchmark, replacing it with the new POLSTR rate starting January 2027. This change will affect millions of mortgage holders and savers using variable-rate products.
The Polish banking sector is undergoing a significant shift in how interest rates are set on mortgages and other variable-rate loans. The National Bank of Poland and the Polish Bank Association announced that from January 1, 2027, banks will no longer grant new loans using the WIBOR (Warsaw Interbank Offered Rate) benchmark. Instead, they will use the newly established POLSTR (Polish Short Term Rate).
What's Changing and Why
WIBOR, which has been Poland's primary interbank lending rate for decades, is being phased out in an "orderly sunset." The overnight WIBOR variants (WIBID O/N and WIBOR O/N) stopped publishing on October 1, 2026, and longer tenors will follow. Existing loans referencing WIBOR will continue unaffected until December 31, 2036, but all new mortgages, business loans, and deposit agreements will reference POLSTR going forward.
POLSTR is designed to be more resilient and transparent, aligned with European benchmark reforms. The Polish Bank Association is working with banks to develop guidance on how to smoothly transition customers from old to new rates, including helping mortgage holders understand what the change means for their monthly payments.
Monthly Impact: When Do I See Changes?
If you have a variable-rate mortgage referenced to WIBOR 6M (the most common type), your rate will continue using WIBOR until your bank negotiates a transition agreement with you—which must happen before January 2027. Banks are required to offer a fair conversion to POLSTR, but the exact margin and terms may vary. Currently, WIBOR 6M sits around 3.91%, so with a typical bank margin of 2.0 percentage points, a variable mortgage costs around 5.91%.
For expats with mortgages: If you are refinancing or taking out a new loan after January 1, 2027, you will automatically be offered POLSTR-based rates. Talk to your bank now if you have an active variable-rate mortgage and want to understand how and when your rate will transition. Ask about the fallback clause in your contract—most agreements already have one that allows automatic conversion with a small administrative fee. Don't delay; banks are already offering POLSTR products and the deadline is approaching fast.
Sources
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