The transition into late December 2025 and early January 2026 marked a pivotal moment for electricity trading within South-East Europe. Following years characterized by bilateral contracts and risk-averse strategies, organized power markets emerged as the dominant platform for price discovery and risk management. This winter period did not witness a crisis-driven spike in prices; rather, it highlighted a more mature trading landscape, characterized by increased liquidity, robust cross-border flows, and price signals driven by regional fundamentals.
During this timeframe, traders and utilities experienced a unique blend of volatility and depth. Prices fluctuated significantly within weeks, yet trading volumes remained stable. Exchanges across the region—including Hungary, Romania, Serbia, and Bulgaria—demonstrated that South-East Europe has evolved from a passive market to an interconnected network of hubs where real-time monetization of spreads and flow patterns is possible.
Central to this evolution were four key exchanges: HUPX, OPCOM, SEEPEX, and BELEN. Their interactions throughout the winter of 2025–2026 provide insight into the future trajectory of power trading in the region.
A Return to Liquidity Amidst Volatility
The hallmark of late 2025 and early 2026 was the resurgence of liquidity in organized markets. Unlike previous winters where high prices led to diminished trading activity, this period demonstrated that elevated prices could coexist with increasing traded volumes. This shift indicates a transition from defensive trading behavior to a more active market participation.
In Serbia specifically, the SEEPEX exchange reported daily trading volumes ranging from 12.9 to 16.5 GWh, translating to total monthly volumes between 420–450 GWh. This marked a significant year-on-year increase, reflecting a growing willingness among Serbian market participants to engage in day-ahead price formation rather than relying solely on fixed bilateral contracts.
Price dynamics during January 2026 further reinforced this trend. Day-ahead prices on SEEPEX varied from around €67/MWh on milder days to peaks exceeding €125/MWh during colder spells with tighter system margins. Notably, high prices did not deter market participation; instead, robust volumes persisted even on peak-price days, indicating confidence in market mechanisms.
The Role of HUPX as a Regional Anchor
The Hungarian exchange, HUPX, continued to serve as the central anchor for power trading in South-East Europe. With average daily day-ahead volumes typically ranging between 70–80 GWh, HUPX provided significant liquidity compared to its neighbors. This depth is crucial as it stabilizes regional price expectations and serves as a reference point for forward hedging.
In December 2025, average day-ahead prices on HUPX hovered around €110–120/MWh, reflecting seasonal demand increases and carbon costs while remaining lower than crisis-era peaks. Traders across the region increasingly relied on HUPX as a benchmark for evaluating spreads on smaller exchanges like SEEPEX and BELEN.
Romania’s Strategic Positioning
OPCOM, Romania’s exchange, played a dual role during this winter season as both a significant domestic market and an essential transit hub connecting Central and South-East Europe. Average day-ahead prices on OPCOM ranged from €115–120/MWh, aligning closely with Hungarian prices but exhibiting variations due to domestic generation factors.
A notable trend was Romania’s bidirectional trading with Hungary and Bulgaria, where electricity was both imported and exported based on prevailing price conditions. This flexibility indicates an integrated market dynamic where traders can respond swiftly to short-term demand fluctuations rather than being confined to static export or import roles.
Bulgaria’s Growing Market Participation
Bulgaria’s exchange, BELEN, historically viewed as less liquid than its northern counterparts, showed signs of increased participation during the winter months. While it did not achieve immediate parity with larger exchanges, BELEN’s prices closely tracked regional movements, indicating deeper engagement with neighboring markets.
The exchange’s relevance lies in its emerging role as a conduit between Balkan markets and Greece. Improved interconnector utilization allowed BELEN prices to reflect broader regional supply-demand dynamics rather than being isolated from external influences.
The Importance of Cross-Border Flows
A defining characteristic of the winter period was the critical role of cross-border flows in shaping price formation across South-East Europe. The region is increasingly moving away from semi-isolated national markets toward a more integrated framework where price signals are rapidly transmitted along key corridors such as Hungary-Romania-Serbia-Bulgaria.
Utilization rates for interconnectors remained high throughout December 2025, with flows shifting direction based on relative price spreads. Serbia’s pricing dynamics were particularly sensitive; when SEEPEX prices fell below those on HUPX, exports became favorable. Conversely, fluctuations in Hungarian pricing prompted imports back into Serbia.
A Structured Approach to Volatility
The volatility observed during January 2026 was characterized by identifiable drivers such as cold weather impacts on demand and variations in hydroelectric availability. This structured volatility contrasts sharply with previous periods defined by panic-driven price spikes or regulatory upheaval.
This environment rewarded proactive management strategies among industrial consumers and generators alike. Flexible load management allowed industrial users to adjust consumption during peak pricing hours while generators optimized dispatch based on real-time pricing signals.
Implications for Market Participants
The developments witnessed during the winter of 2025–2026 underscore several strategic realities for market participants in South-East Europe. Organized exchanges are now essential not only for effective price discovery but also for comprehensive risk management strategies. Furthermore, awareness of cross-border dynamics has become crucial for profitability in trading operations.
The deepening liquidity within core hubs supports increasingly sophisticated trading strategies encompassing spread trading and portfolio hedging. Industrial consumers are also adapting their approaches; many now view exchange prices as valuable reference points for procurement decisions rather than threats.
Toward Integrated Markets
The trends observed during late 2025 and early 2026 suggest that South-East Europe is progressing towards greater integration with the EU internal electricity market. As regulatory frameworks align further and market coupling initiatives advance, the distinctions between regional trading hubs will continue to diminish.
This evolution does not signify an end to opportunities within the market; instead, it highlights that value creation will increasingly depend on operational excellence and timely information rather than mere geographical arbitrage. The winter period should be viewed not as an isolated event but as indicative of an ongoing transformation within South-East Europe’s power markets.
