A variable-rate mortgage payment has two parts: WIBOR 3M plus the bank margin. Margin is fixed, WIBOR is not. The bank rechecks WIBOR every 3 months and recomputes the payment. Example: 400 000 PLN mortgage over 30 years, 2.4% margin. In January 2022 WIBOR 3M sat at 2.25% — payment around 1 800 PLN. In October 2022 WIBOR jumped to 7.20% — the payment leapt to 3 000 PLN. The hit is the same as taking a fresh cash loan of a few tens of thousand PLN.
The critique of WIBOR has two layers. Method: WIBOR is built from bank quotes, but since 2015 banks rarely actually lend to each other at these prices. The index is based on declarations, not transactions. Level: critics argued WIBOR in 2021–2023 sat above the real funding cost of banks, so mortgage borrowers overpaid. This critique drove the planned migration from WIBOR to WIRON starting in 2025.
The WIRON migration is a key 2025–2026 event. New Polish mortgages from 2025 are based on WIRON, not WIBOR. Existing WIBOR mortgages are being migrated to WIRON through annexes — the process will run until 2027. For the borrower WIRON usually means a payment 0.3–0.7 pp lower than WIBOR at the same moment, though the annex may add a small margin tweak to balance the switch.
Frequently asked questions
Around 4.5% in June 2026. History: peak 7.20% (October 2022), trough 0.17% (March 2021). Check the live figure on GPW Benchmark.
On a WIBOR 3M mortgage — every 3 months. The bank updates the payment to the WIBOR on the check date, usually the first instalment date of each quarter.
In theory yes, in practice no. The lowest recorded WIBOR 3M is 0.17% in March 2021. Even if it went negative, contracts usually contain a „not below zero" clause protecting the bank.