The European Commission said the surplus of carbon allowances in the EU’s main carbon market totalled 1,023,494,202 in 2025, a figure used to set how many permits are moved in and out of a market buffer.
The number is known as the total number of allowances in circulation, or TNAC, and is published once a year under the EU Emissions Trading System (EU ETS), the bloc’s cap-and-trade scheme that requires power plants, factories and other covered sectors to hold permits for their CO₂ emissions.
The TNAC is used to run the Market Stability Reserve (MSR), a mechanism that adjusts auction volumes by moving allowances into a reserve when there is a large surplus, or releasing them when there is a shortage, the Commission explained in a statement on Friday.
Based on the latest TNAC, 190,494,202 allowances will be placed in the MSR over 12 months from 1 September 2026 to 31 August 2027.
Auction volumes are expected to fall as a result, with the change to be reflected in auction calendars due to be adopted around July 2026.
What is happening inside the Market Stability Reserve
There were 400 million allowances in the MSR on 1 January 2026, the Commission said.
Allowances held in the MSR above that level are no longer valid, under existing rules.
The Commission proposed an amendment in April 2026 to stop that invalidation mechanism, and said that until any change takes effect, the number of allowances added to the reserve will continue to be calculated under the current MSR rules.
The next TNAC figure is due to be published by 1 June 2027.
