The SOFIX index, which includes the 20 most liquid stocks on the Bulgarian Stock Exchange (BSE), dropped 3.31% to 472.05 points, while the broader BG 40 index, which tracks the 40 most traded shares on the bourse, lost 4.04% to 140.57.
BSE's turnover, excluding block and other pre-agreed deals, fell to 1.45 million levs ($956,000/741,000 euro) from 3.5 million levs on Wednesday.
On Thursday, fallers led gainers by 59 to 31 and eight stocks closed unchanged.
Blue-chip lender Central Cooperative Bank traded most on Thursday, Sofia-based Bull Trend Brokerage said in a daily note. The bank's shares of the bank plummeted 8.11% to 1.3 levs in a volume of 213,183 stocks.
Industrial groups Industrial Holding Bulgaria, Doverie United Holding, Chimimport and lender First Investment Bank (FIB) and financial and insurance group Eurohold Bulgaria lost between two and seven percent, Bull Trend added. Trading in the companies was in small volumes.
Industrial Holding Bulgaria lost 6.02% to 2.65 levs, Doverie ended 2.08% lower at 7.5 levs, Chimimport closed 5.44% lower at 2.9 levs, FIB dropped 5.06% to 3.76 levs and Eurohold Bulgaria fell 1.89% to 2.23 levs.
The BG TotalReturn30 (BG TR30) index, in which companies with a free float of at least 10% have equal weight, fell 3.11% to 354.71 points and the BG-REIT index, tracking the performance of real estate investment trusts, ended 0.82% lower at 53.54.
The Dnevnik 20 index, calculated by local business daily Dnevnik from the share prices of the 20 leading companies in terms of liquidity and market capitalisation, dropped 3.17% to 70 points.
(1 euro = 1.95583 Bulgarian levs)