“Amid our continuous monitoring role, we concluded there was a need to temporarily suspend trading in INA shares to protect interests of all investors and ensure transparency, after we determined a major involvement of foreign investors in trading in INA shares,” HANFA said in a statement quoted by Reuters.

Trade in the shares was suspended until April 1.

MOL owns 47.25% of INA and the Croatian government holds 44.84%.

MOL made a public purchase offer for the 8% of INA shares in free float last December. MOL offered HRK 2,800 per share, the same as the price in a public purchase offer it made in the autumn of 2008. But other market players appeared to outbid MOL, pushing the share price over the offer. MOL raised its stake by just 0.1% in the offer.

Reuters said there has been market speculation in recent weeks that an investment fund originating in Cyprus was acquiring INA shares.