The SOFIX index, which includes the 20 most liquid stocks on the Bulgarian Stock Exchange (BSE), plunged 8.44% to 548.02 points, while the broader BG 40 index, which tracks the 40 most traded shares on the bourse, dropped 5.98% to 149.62.
"The word that marked everything today was fear. Fear about global growth, about slowing consumption hitting sales and earnings, and about the alarming decrease in oil prices which suggests an economic slowdown and recession," Angel Dimitrov, a broker with Ug Market brokerage, told SeeNews.
BSE's turnover, excluding block and other pre-agreed deals, rose to 5.1 million levs ($3.3 million/2.6 million euro) from 2.8 million levs on Thursday.
On Friday, fallers led advancers by 74 to 13, with 13 shares closing flat.
Among the biggest losers were subsidiaries of blue-chip industrial conglomerate Chimimport which earlier on Friday announced plans to seek some 200 million levs in a 50 million-share capital hike.
"The market did not take the news well," Dimitrov said.
Blue-chip lender Central Cooperative Bank (CCB) and grain and oilseed trader Zarneni Hrani lost 17.44% to 1.74 levs and 7.4% to 1.0 lev, respectively. Shares of Chimimport dropped 7.85% to 3.4 levs as 93,220 stocks changed hands.
Zinc and lead smelter OTZK was the biggest loser among the blue chips on the BSE. Shares of the company sank 27.27% to 12 levs in a volume of 5,733 shares.
"OTZK lost some 30-40% within a week as lead and zinc prices worldwide fell," Dimitrov said.
The BG TotalReturn30 (BG TR30) index, in which companies with a free float of at least 10% have equal weight, lost 6.38% to 384.61 points and the BG-REIT index, tracking the performance of real estate investment trusts, inched 0.28% higher to 57.35.
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, lost 3.37% to 77.71 points.
(1 euro = 1.95583 Bulgarian levs)