Bulgaria has made significant progress in establishing a domestic Guarantees of Origin (GO) market since launching auctions on the Independent Bulgarian Energy Exchange (IBEX) in July 2025. Trading activity has increased steadily and RES-E GO issuance reached record levels during 2025.

However, Bulgarian RES-E GOs continue to trade at about 80 % discount to equivalent European certificates because they remain outside the AIB Hub, which enables cross-border trading, and participation is limited to a relatively small domestic buyer base.

Unlike most mature GO markets, Bulgarian auction prices are strongly linked to the remaining validity of certificates, creating a pronounced expiry discount that reflects limited domestic liquidity and the inability to transfer certificates freely across Europe. The eventual connection of Bulgaria to the AIB Hub would fundamentally change this local market dynamic and also decrease the discount of Bulgarian GOs relative to other EU AIB markets.