Information about benchmarks

Changes in benchmarks – what you should know

For many years, the regulations concerning interest rate reference benchmarks have been changing.
This includes such benchmarks as: WIBID, WIBOR, EURIBOR or LIBOR.  In the European Union, the basis for these changes is the BMR Regulation (BMR), a document that sets out how benchmarks should be developed.
As a result of the changes, the calculation methodology of certain benchmarks (e.g. EURIBOR) has been adjusted or they have been replaced with new ones (e.g. CHF LIBOR has been replaced by SARON).  Work is in progress on some of the benchmarks.

What is the situation in Poland?

In Poland, the most commonly used benchmarks are WIBID and WIBOR.  The development of these benchmarks is the responsibility of GPW Benchmark S.A. which is supervised by the Polish Financial Supervision Authority (KNF).

At the same time, work is underway to introduce a new benchmark, conducted by:

• Administrator – GPW Benchmark S.A., responsible for administering these benchmarks, and
• the National Working Group for the reform of reference benchmarks (NGR) which includes representatives of the KNF, the Ministry of Finance, the Bank Guarantee Fund, the National Bank of Poland and the banking sector. 

In December 2024, the NGR announced that the new benchmark on the Polish financial market will be POLSTR, which will replace the currently used WIBID and WIBOR.

When will the changes take place?

• As of October 1, 2026, WIBID O/N and WIBOR O/N will no longer be published, i.e. the overnight reference rates determined for one business day.
• As of January 1, 2027, the Bank will no longer offer products based on WIBOR.
• As of January 1, 2037, WIBID and WIBOR for the 1M, 3M and 6M tenors (one month, three months and six months) will no longer be published.

What are we doing for you to prepare for the changes?

We have prepared a fallback plan so that your agreements will function correctly after a material change to the benchmark or after its discontinuation.

• We have introduced appropriate provisions into concluded agreements, known as fallback clauses, which describe the procedures to be followed in the event of a temporary or permanent cessation of publication of the benchmark or its material change.
• We are working on the introduction of the POLSTR benchmark in new products and services.

We will introduce the changes in accordance with legal regulations and the provisions of the agreements.  All information important will be available on our websites.

Changes for Corporate Customers Using Deposit Products Based on WIBID O/N and WIBOR O/N

Which rate will replace WIBID O/N and WIBOR O/N?

SME and corporate customers holding deposit products will receive individual notifications regarding the change. The communication will inform them that, effective October 1, 2026, POLSTR will replace WIBID O/N or WIBOR O/N, as applicable.

On December 10, 2024, POLSTR was designated by the National Working Group (NGR) as the target interest rate benchmark to replace the WIBOR benchmark (initially operating under the technical name WIRF-). As of September 2, 2025, POLSTR has held benchmark status in accordance with the requirements of the BMR.

Why is an adjustment required?

POLSTR differs from WIBID O/N and WIBOR O/N. Although these rates measure closely related underlying markets, they are calculated using different methodologies. To make the transition as neutral as possible for both customers and the Bank, POLSTR will be increased or decreased by an appropriate adjustment spread.

How will the adjustment for WIBOR O/N be determined?

For WIBOR O/N, the Bank will apply the adjustment spread calculated and published by Bloomberg (Bloomberg Index Services Limited), an independent entity designated by the International Swaps and Derivatives Association (ISDA) as the official provider of adjustment spread calculations under the IBOR Fallbacks framework.

The adjustment was calculated in accordance with the international ISDA methodology as the median historical difference between WIBOR O/N and POLSTR over a five-year observation period. The adjustment value was fixed on September 30, 2025.

How will the adjustment for WIBID O/N be determined?

Bloomberg has not published an adjustment spread for WIBID O/N, as this benchmark is not covered by the ISDA mechanism.

Therefore, the Bank has calculated the adjustment independently, using:

• the same ISDA methodology,
• the same historical observation period,
• the same assumptions that were applied for WIBOR O/N.

Why was this approach selected?

The Bank considers this approach the most appropriate because it:

• Complies with international standards – it is based on the ISDA framework, a globally recognized market standard developed through market consultations and with regulatory support.
• Ensures a consistent approach for WIBOR O/N and WIBID O/N – the same methodology and observation period used by Bloomberg for WIBOR O/N have been applied to WIBID O/N.
• Supports economic neutrality – the adjustment and its calculation methodology are designed to minimize value transfer between parties and limit changes in interest rates at the time of benchmark replacement.

Additional Information on the Adjustment Methodology

ISDA / Bloomberg – IBOR Fallback Rate Adjustments Rule Book:
https://assets.bbhub.io/professional/sites/27/IBOR-Fallback-Rate-Adjustments-Rule-Book_V6.2_Sep2025.pdf It will open in a new window

ISDA / Bloomberg – Technical Note: PLN WIBOR Tenor Cessation (WIBOR O/N adjustment):
https://assets.bbhub.io/professional/sites/27/IBOR-Fallbacks-PLN-WIBOR_Tenor-Cessation_Technical-Note_251222.pdf It will open in a new window

Answers to frequently asked questions

When will the POLSTR benchmark be introduced to new agreements? 
We plan to offer new products based on POLSTR in 2026.

When will the benchmarks change in agreements that are already in force?

• O/N WIBID and O/N WIBOR  – October 1, 2026 – based on provisions already included in the agreement (the fallback clause) or after signing an annex.
• 1M, 3M, 6M WIBOR – January 1, 2037 – based on GPW Benchmark’s decision to discontinue the development of WIBOR under an orderly wind-down process.

Will POLSTR-based products be cheaper than WIBOR-based?
The objective of the benchmark reform is not to reduce interest rates.

In the case of agreements that are already in force, EU regulations (the BMR) and national regulations provide for the possibility of applying an adjustment so that the change of the benchmark is neutral for both parties. The method of determining the adjustment will be set out in legal regulations or in the provisions of customers’ agreements.

Do customers need to do anything now?
In most cases, customers will not need to take any action. If this changes, we will inform them well in advance. In selected cases, customers will receive a proposal to sign an amendment agreement changing the reference rate used as the basis for interest calculation before October 1, 2026.