Bulgaria is set to adopt the euro on 1 January 2026, becoming the 21st member of the euro area. While the political and logistical preparations continue at national level, the European Central Bank has already outlined a set of transitional arrangements meant to make the financial switch smoother—especially for Bulgaria’s banking sector as it becomes part of the Eurosystem’s mandatory reserve framework.
Once the euro becomes Bulgaria’s currency, banks operating in the country will be required to hold minimum reserves under Eurosystem rules—meaning a defined portion of certain liabilities must be kept as deposits with the central bank. The ECB’s decision acknowledges, however, that the changeover comes at an awkward moment in the reserve calendar. Under Bulgaria’s existing schedule, the reserve-maintenance period running from 23 December 2025 to 10 February 2026 overlaps directly with the euro’s introduction. In practice, that overlap could have forced banks into an abrupt mid-period regulatory shift, increasing operational risk and administrative burden precisely when systems, reporting and payment infrastructure are being adapted to the new currency.
To prevent unnecessary disruption, the ECB предусмотрes a short, clearly defined “soft landing” at the start of 2026. During the first month after accession—up to 10 February—new reserve rules are to be introduced gradually, with special technical provisions for how reserves are calculated and maintained during the transition. The goal is not to relax the long-term obligations, but to avoid confusion, extra paperwork and unintended mismatches in reporting during a period when banks are already managing one of the biggest changes in the country’s monetary history.
The transitional approach also accounts for the wider euro-area banking network. The ECB noted that, for a limited time, institutions in other euro-area countries will be able to deduct exposures to Bulgarian banks from their own reserve base. This option is also described as applying to the period from 11 February to 24 March 2026. In essence, these technical adjustments are meant to reduce the risk of accidental distortions in statistics and interbank settlements at the moment Bulgarian banks shift status—from “outside the euro area” to fully inside it—during an ongoing reserve-maintenance cycle.
Importantly, the ECB stresses that such measures are not exceptional in principle: similar transitional rules have been used during earlier euro-area enlargements. Their purpose is to preserve continuity and predictability for day-to-day banking operations while the new member state is integrated into the single reserve mechanism. For Bulgaria, the message is straightforward: the euro changeover is designed to be decisive, but not disruptive—and the first weeks of 2026 are intended to give the financial system a controlled, manageable runway into full Eurosystem procedures.
