Fondul Proprietatea is looking to sell up to 19.243 million Romgaz shares.
Goldman Sachs International will act as the sole bookrunner for the transaction, while Erste Group Bank AG will act as joint lead manager, the fund said in a stock exchange filling.
Romgaz is 70%-owned by the Economy Ministry, while Fondul Proprietatea holds a 14.99% stake.
Monday, Romgaz closed down 0.42% at RON35.6 a share in Bucharest, valuing the company at RON13.72 billion.
Fondul Proprietatea was set up in 2005 to compensate Romanians whose properties were seized during communism.
The fund has stock in over 80 companies, including dominant oil company OMV Petrom (SNP.RO), power companies Transelectrica (TEL.RO), Nuclearelectrica, Hidroelectrica and gas companies Romgaz and Transgaz (TGN.RO). (EUR1=RON4.3993)