In this joint letter to the European Commission, Carbon Market Watch and allied NGOs demand that the EU executive refrain from meddling with the Market Stability Reserve, which underpins the EU’s Emissions Trading System and safeguards the carbon price by soaking up excess liquidity in the market. Specifically, the letter calls for the protection of the MSR’s invalidation which has so far allowed for the cancellation of 3.4 billion excess allowances and prevented an equal amount of CO2 tonnes from ever being released into the atmosphere.