Donev acquired the shares through deals on the Bulgarian Stock Exchange on December 3, Sopharma said in a bourse filing.
The 23,771 shares are equal to a 0.005% stake in Sopharma.
At the end of September, Donev held a stake of below 5% in Sopharma, according to the company's most recent interim financial statement.
However, Ognyan Donev is indirectly the biggest shareholder in Sopharma, as he controls a 25.39% stake through his company Donev Investments Holding. Donev is also a major shareholder in Sopharma's second biggest shareholder - Telecomplect Invest. Telecomplect Invest controls 20.68% interest in Sopharma.
Sopharma shares closed at 3.39 levs on the Bulgarian Stock Exchange on Tuesday.
(1 euro = 1.95583 levs)