ACM launches investigation into the financial returns of four heat suppliers

The heat suppliers’ financial returns on their supply to households and other small-scale users in 2024 ranged from -56 percent to 15 percent. This has been revealed in an investigation by the Netherlands Authority for Consumers and Markets (ACM). At four suppliers, the financial returns were higher than the reasonable return of 6.8 percent. ACM will conduct a return assessment at these 4 suppliers to find out why their returns in 2024 were higher than the standard. If ACM’s investigation shows that the financial returns in 2025 are also higher than the standard, ACM can force the suppliers to adjust their tariffs for the year 2027.

Protecting heat users

To protect heat users against unreasonably high tariffs, ACM sets maximum tariffs each year. These maximum tariffs apply to all households and other small-scale users that are connected to a heat network. However, these maximum tariffs do not apply to large-scale users such as large companies that are connected to a heat network. Heat suppliers are allowed to earn a reasonable return, but cannot use the maximum tariffs for households to make unreasonably high profits. That is why ACM keeps an eye on the financial returns of heat suppliers, and sets a standard return.

There can be various reasons for higher or lower financial returns of a heat supplier, for example, because of differences in purchasing strategies as well as different types of sources and technologies. ACM does not see a clear correlation between the age or size of a heat network and the financial returns of the supplier. ACM does see that the average financial returns of heat suppliers are going down. Almost half of the heat suppliers make negative financial returns on the supply of heat to households and other small-scale users. Negative financial returns make it more difficult for heat suppliers to invest in existing or new heat networks. That is why low financial returns can be a threat to the heat transition. In the National Climate Agreement (in Dutch: Klimaatakkoord), it has been agreed that natural gas must be phased out of all homes by 2050. The construction of heat networks is one important route in reaching this goal. Last year, approximately 22,000 households were connected to heat networks of licensed suppliers. The number of households connected to heat networks has thus reached over 700,000.

Better insight thanks to tightened accounting rules

The 2024 Financial-return Monitor is the first monitor drawn up on the basis of the tightened accounting rules (RAR). Thanks to these rules, ACM has better insight into the financial returns of heat suppliers, for example, into the difference between the supply to households and the supply to large-scale users. In practice, it is always the case that both households and large-scale users are connected to a heat network. However, ACM’s maximum tariffs and standard return only apply to the supply to households.

Preparing for the Dutch Collective Heat Act

Over the next two years, ACM is making the necessary preparations for the new method for tariff regulation as laid down in the new Dutch Collective Heat Act (in Dutch: Wet collectieve warmte, Wcw). This law is expected to come into effect on 1 January 2027. Under the new act, the link between the maximum heat tariffs and the price of natural gas (the ‘no-more-than-otherwise principle’) will be gradually phased out, but ACM will base the tariffs on the actual costs of suppliers. That is why it is important that ACM has a good overview of the actual costs of suppliers.

See also

• 14-01-2026 2024 Financial-returns Monitor for heat suppliers (in Dutch)
• 09-10-2025 Amended decision regarding reasonable returns of heat suppliers and amended policy rule regarding the return assessment for heat (in Dutch)

See also

• 24-06-2026 ACM investigation: heat suppliers did not earn unreasonable profits, ACM to continue to keep a close watch on financial returns