1. Legislative context

Electricity and gas traders who supply electricity or gas to consumers and self-employed individuals under fixed-price electricity or gas supply contracts^[1] are required, under the relevant provisions of the Energy Act,^[2] to determine the value of the trader’s security index (hereinafter referred to as “TSI“) on 31 March and 30 September of each year. They are then obliged to notify the Energy Regulatory Office (hereinafter referred to as “ERO“) of the TSI value and publish it on their websites.

2. Method of publishing the trader’s security index value

In its communication of 5 December 2025,^[3] the ERO calls on traders to publish the TSI value in a visible, easily accessible and traceable manner:

• directly on the home page, or via a link with the wording “security index”;
• the web page with the TSI value must be searchable via a web browser by entering the combination of the supplier’s name + “security index”;
• the TSI value must be accompanied by the date on which the value was determined and the date of its publication.

All this information must be organised in such a way that it is visible simultaneously on the screen of commonly used mobile devices. If more than one TSI value is published on the website, the most recent value must always be listed first.

3. Relationship to the right of consumers and self-employed persons to terminate a contract

According to the Energy Act, if a trader does not publish the TSI value (or if this value is lower than 70%), consumers and self-employed individuals are entitled to terminate the contract for the supply of the relevant commodity.^[4] However, this right expires when the TSI value is published by the trader, even if there is a delay, as the “objective of transparent information on the trader’s business conduct” is still fulfilled.

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[1]     A fixed-price contract for the supply of electricity or gas is defined in Section 2(1)(l) of Act No. 458/2000 Coll., on the conditions for doing business and the exercise of state administration in the energy sectors, as amended (for the purposes of this document, referred to as the “Energy Act”) and is understood to mean a contract in which the price of the relevant commodity is agreed at a precise amount for an agreed period of time, provided that the electricity or gas trader is not entitled to unilaterally change the amount or otherwise change the agreed price for this agreed period.

[2]     These provisions refer to Section 30(2)(s) of the Energy Act (in the case of electricity supply) and Section 61(2)(q) of the Energy Act (in the case of gas supply).

[3]     The relevant ERO communication is available here (in Czech): https://eru.gov.cz/sdeleni-o-zpusob-zverejneni-indexu-obchodnika-o-zaniku-prava-na-vypoved-smlouvy.

[4]     See Section 11a(11) of the Energy Act. In such a case, the notice period ends on the last day of the calendar month following the month in which the notice of termination was delivered to the trader.

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This material is for general information on current topics only, it is not advice. It does not take into account any special circumstances, financial situations or special requirements of the addressees. Recipients should therefore always seek appropriate professional services for the information provided. Notwithstanding the careful compilation of this material, bpv Braun Partners s.r.o. advokáti, its partners, associates or co-operating solicitors and tax advisers cannot guarantee the accuracy or completeness of the information contained herein and accepts no responsibility for acting or refraining from acting on the basis of the information contained in this material