Information about benchmarks

The Bank uses interest rate benchmarks in many contracts and financial instruments. The benchmarks we use include, for example, WIBOR, POLSTR, EURIBOR, and SARON.

The principles governing the development and use of benchmarks in the European Union are set out in the BMR Regulation. In line with its requirements, benchmark administrators may change the methodology used to determine benchmarks, introduce new benchmarks, or discontinue those that have been published to date.

In Poland, the administrator of benchmarks is GPW Benchmark S.A., which operates under the supervision of the Polish Financial Supervision Authority (KNF). In cooperation with the National Working Group on Benchmark Reform (NGR), GPW Benchmark S.A. established the new POLSTR benchmark and subsequently decided on the orderly discontinuation of the WIBID and WIBOR benchmarks.

As the target benchmark for the Polish financial market, POLSTR is intended to be used in newly concluded agreements and to gradually replace the WIBID and WIBOR benchmarks that are being phased out.

When will the changes take place?

• From 26 September 2026, the Bank will offer mortgage loans based on POLSTR 1M Compounded Rate, complementing the range of POLSTR-based products already offered to customers.
• From 1 October 2026, WIBID O/N and WIBOR O/N, i.e. benchmarks determined for a one-business-day tenor, will no longer be published.
• From 1 January 2027, the Bank will no longer enter into agreements for products based on WIBOR.
• From 1 January 2037, WIBID and WIBOR for the 1M, 3M and 6M tenors, i.e. one month, three months and six months, respectively, will no longer be published.

What does this mean for you?

• If you enter into a new PLN loan agreement with a variable interest rate, the Bank will offer a product based on the POLSTR benchmark. The agreement will include procedures (fallback clauses) to be followed in the event of a temporary or permanent cessation of publication of the benchmark or a material change to its methodology.
• If you have a product based on WIBID O/N or WIBOR O/N, the Bank has contacted you and explained how your agreement will continue after publication of the benchmark ceases. Any changes will be implemented in accordance with the applicable laws and the provisions of your agreement.
• If you have a product based on WIBOR 1M, 3M or 6M, we will inform you how your agreement will continue after these benchmarks are discontinued closer to the date on which their calculation ceases.

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?

From 1 October 2026, in deposit products for SME and corporate customers, the WIBID O/N and WIBOR O/N benchmarks will be replaced by the POLSTR benchmark, which:

• was designated by the NGR on 10 December 2024 as the target benchmark intended to replace the WIBOR benchmark,
• has held benchmark status since 2 September 2025 in accordance with the requirements of the BMR Regulation,
• was designated as a significant benchmark by the KNF on 21 August 2026.

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 30 September 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?

From 26 September 2026, the Bank will offer mortgage loans based on the POLSTR 1M Compounded Rate, complementing the range of products already offered to customers that use POLSTR.

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 have been provided with a proposal to sign an amendment changing the reference rate currently applied to their agreement.