(Adds details, Italgas CEO comment)

By Francesca Landini

MILAN, Oct 5 (Reuters) - Italy's biggest gas distributor Italgas said on Saturday it had agreed to buy smaller rival 2i Rete Gas in a 5.3 billion euro ($5.8 billion) deal, including debt.

A merger would mark a major step in the consolidation of Italy's gas distribution sector and also create a leading player in Europe, Italgas CEO Paolo Gallo said in a statement.

The equity value of the transaction is 2.06 billion euros, while 2i Rete Gas' net financial debt and other net liabilities at the end of 2023 amounted to 3.246 billion euros, Italgas said.

The gas distributor will cover the cost of the deal via a bridge financing initially underwritten by JP Morgan and syndicated to a group of banks including Banco BPM, BofA Securities, Citi, JP Morgan, Morgan Stanley and Société Générale.

It will then launch a 1 billion euro rights issue to refinance the bridge loan with the goal of maintaining its current credit rating profile.

Italian infrastructure fund F2i has a 64% stake in 2i Rete Gas. Dutch pension fund APG and buyout group Ardian together hold the remaining 36.1% under the vehicle Finavias.

Closing of the transaction is expected in the first half of 2025, subject to regulatory approvals.

Gas distribution is a regulated business in Italy with the country's energy authority responsible for setting fees on the fuel transport and returns on investments needed to upgrade the network.

JP Morgan acted as financial adviser for Italgas, Legance served as legal adviser, and Foglia and Partners was responsible for tax matters. Rothschild supported Finavias on the deal.

JP Morgan, BofA Securities and Jefferies have provided a fairness opinion to Italgas' board regarding the deal.

($1 = 0.9111 euros)

(Reporting by Francesca Landini Editing by Mark Potter)

((francesca.landini@thomsonreuters.com; +39 02 66129437; Reuters Messaging: reutersitaly.thomsonreuters@reuters.net))