The European Central Bank has set transitional rules for minimum reserve requirements as Bulgaria prepares to adopt the euro on January 1, 2026. These provisions aim to smoothly integrate Bulgarian banks into the Eurosystem without undue burden. The decision follows the ECB's Executive Board adoption on September 23, 2025.
On September 23, 2025, the Executive Board of the European Central Bank (ECB) adopted Decision ECB/2025/33, establishing transitional provisions for minimum reserve requirements following Bulgaria's euro introduction on January 1, 2026.
As of that date, credit institutions and their branches in Bulgaria—referred to as "institutions"—will become subject to the Eurosystem’s minimum reserve requirements. The regular reserve maintenance period spans from December 23, 2025, to February 10, 2026, necessitating these transitional measures to ensure smooth integration.
The provisions include a dedicated transitional maintenance period from January 1 to February 10, 2026, for imposing requirements on Bulgarian institutions. They also outline specific rules for applying minimum reserves during this time and a method for calculating the reserve base related to liabilities owed to Bulgarian institutions.
Institutions in other euro area countries have the option to deduct liabilities owed to Bulgarian institutions from their reserve base for two periods: December 23, 2025, to February 10, 2026, and February 11 to March 24, 2026. This approach aligns with precedents set when other countries joined the euro area.
The decision, which mirrors past integrations, will be published in the Official Journal of the European Union. It underscores the ECB's efforts to maintain price stability across the euro area while accommodating new members like Bulgaria.
For context, the Eurosystem’s minimum reserve system requires institutions to hold a fraction of certain liabilities as reserves with central banks, helping to control liquidity and support monetary policy transmission.