MCO function (Market Coupling Operator function)
The MCO function is the set of tasks needed to match day-ahead and intraday orders across bidding zones while simultaneously allocating cross-zonal capacity. Under CACM, NEMOs establish and perform this function for single day-ahead and intraday coupling; it is a shared function, not a separate exchange.
The Market Coupling Operator function, or MCO function, is the set of tasks needed to match orders from day-ahead and intraday markets across bidding zones while simultaneously allocating cross-zonal capacity. Under CACM, NEMOs are responsible for establishing and performing this function for single day-ahead and intraday coupling.
What the function includes
The MCO function is not a company name. It is a functional layer: receiving order books and network data, running the matching algorithm, validating outputs and returning prices, net positions, scheduled exchanges and trade information to NEMOs and TSOs. In the day-ahead timeframe, the visible algorithmic core is EUPHEMIA; in the intraday timeframe, the function connects the SIDC shared systems.
Why the distinction matters
A trader normally deals with Nord Pool, EPEX or another NEMO. The MCO function is the shared European process behind those local interfaces. That is why different NEMOs in the same bidding zone can publish the same coupled price: their orders are cleared through the common function rather than through isolated national auctions.
Sources
CACM Regulation Article 2 and Article 7 · NEMO Committee glossary