Sopharma bought the shares at a price of 5.50 levs ($3.43/2.81 euro) apiece on the Bulgarian Stock Exchange's regulated market, Sopharma Trading said in a bourse filing.
Since the start of December, Sopharma has acquired 15,929 shares in Sopharma Trading.
Sopharma held a 76.09% stake in Sopharma Trading at the end of September.
As at 15:25 CET on Thursday, shares in Sopharma traded 1.24% lower at 3.18 levs, while shares in Sopharma Trading were flat at 5.50 levs.
(1 euro = 1.95583 levs)