The SOFIX, which tracks the 15 most liquid shares on the Bulgarian Stock Exchange (BSE), ended 0.26% higher at 333.28 points, after falling by 0.57% on Wednesday.
The broader BG40, which includes the 40 most traded shares, fell 0.19% to 121.66 points after losing 0.16% in the previous trading session.
Total turnover on the regulated market fell to 406,679 levs ($265,000/208,000) from 637,900 levs on Wednesday.
Four of the 12 SOFIX components that were traded on Thursday advanced, seven fell and one ended flat.
Industrial group Chimimport [BUL:6C4] was the top SOFIX gainer, closing 2.78% higher at 0.78 levs as 2,304 shares changed hands.
Financial and insurance group Eurohold Bulgaria [BUL:4EH] was the top blue-chip decliner, closing 1.68% lower at 0.88 levs in a volume of 200 shares.
The BG-REIT index, which tracks the performance of real estate investment trusts, ended 0.05% lower at 80.71 points after rising by 0.01% on Tuesday.
The BG TotalReturn30, in which companies with a free float of at least 10% have equal weight, lost 0.56% to 252.97 points, following a 0.69% decrease in the previous trading session.
The CGIX Corporate Governance index, which includes companies strictly applying corporate governance principles, ended 1.54% lower at 75.69 points. It fell 0.53% on Wednesday.
(1 euro = 1.95583 Bulgarian levs)