GME organises and manages the natural gas market (MGAS). In the MGAS, parties authorised to carry out transactions at the “Punto Virtuale di Scambio” (PSV - Virtual Trading Point) may make spot purchases and sales of natural gas quantities.

In the MGAS, GME plays the role of central counterparty of the transactions concluded by Market Participants.

The MGAS consists of:  

• Day-Ahead Gas Market (MGP-GAS). The MGP-GAS takes place in two successive stages; in the first stage, transactions take place under the continuous-trading mechanism; in the second stage, they take place under the auction-trading mechanism. In the MGP-GAS, gas demand bids and supply offers, in respect of the calendar gas-day following the one on which the auction-trading session ends, are selected; 
• Intra-Day Gas Market (MI-GAS). The MI-GAS takes place in a single session under the continuous- trading mechanism. In the MI-GAS, gas demand bids and supply offers, in respect of the gas-day on which the session ends, are selected. 

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For the purposes of the market:

1. applicable period: the gas-day (period of 24 consecutive hours beginning at 6:00 a.m. of each calendar day and ending at 6:00 a.m. of the next calendar day);
2. the unit of measurement of the gas quantity is the MWh/day, specified without decimals;
3. the unit of measurement of unit prices is the Euro/MWh, specified with three decimals.

The MGP-GAS consists of:

• continuous-trading session: it opens at 8:00 a.m. of the third day preceding the gas-day to which bids/offers refer and closes at 10:00 a.m. of the day preceding the gas-day to which bids/offers refer;
• closing auction: it takes place in a single session on the day preceding the gas-day to which bids/offers refer. The auction-trading sitting of the MGP-GAS opens at 10:00 a.m. and closes at 11:00 a.m. of the day preceding the gas-day to which bids/offers refer.