The SOFIX index, which includes the 20 most liquid stocks on the Bulgarian Stock Exchange (BSE), plummeted 7.03% to 363.94 points and the broader BG 40 index, which tracks the 40 most traded shares on the bourse, plunged 4.12% to 112.57 at 0903 GMT.
"Everybody is trying to exit the market but there is no liquidity, excluding the deal in Petrol, of course," Razvigor Hristov, an investment consultant with Slovenian-owned KD Securities brokerage in Sofia, told SeeNews.
A total of 2,698,674 shares in Petrol changed hands at 9.1 levs ($5.82/4.6 euro) in a single deal, Hristov said. "There is almost no free float in Petrol. [...] The deal is equal to 3.0% of the capital and there will be no announcement who is the buyer."
Under Bulgarian legislation, the companies are required to disclose the parties only to deals exceeding 5.0% of the capital.
Petrol shares were 0.27% down at 0739 GMT.
BSE’s turnover surged to 25.6 million levs ($16.4 million/13 million euro) at 0903 GMT, compared to 1.5 million levs on Friday.
The BG-REIT index, tracking the performance of real estate investment trusts, inched down 0.55% to 52.16 and the BG TotalReturn30 (BG TR30) index, in which companies with a free float of at least 10% have equal weight, dropped 4.83% to 287.19 points at 0903 GMT.
(1 euro = 1.95583 Bulgarian levs)