The transaction was made on Rasdaq deal market Wednesday.
Fondul Proprietatea bought 797,530 new shares at RON34 a unit, 6.22% higher than the reference price.
Thursday, Conpet traded down 5% at RON32.2 a share, amid a declining market.
Conpet is 58.7%-owned by the Economy Ministry. Investment fund Fondul Proprietatea (FP.RO) controls a 20.05% stake, while other investors own the remaining shares. (EUR1=RON4.262)