The blue-chip SBITOP index of the Ljubljana Stock Exchange (LJSE) lost 3.93% to 1,163.75 and the broader 15-share SBI20 index sank 3.99% to 5,148.60.
Market analysts said movements on the LJSE follow trends on foreign markets. The markets in Asia and Europe recorded heavy losses on Friday on concerns the global recession will hit earnings.
"The red colour prevailed today as well," local brokerage house Ilirika said in a daily note. The Slovenian indices had already notched up negative closes in the two previous days.
All 10 blue chips lost ground on Friday with the country's second largest bank by assets, Nova Kreditna Banka Maribor (NKBM), falling most. It plunged 5.81% to an average price of 15.07 euro ($19.01) on some 45,000 euro of turnover.
NKBM was followed by brewer Pivovarna Lasko, which sank 5.69% to 53.33 euro on some 43,000 euro of turnover.
Shares of heavyweight blue-chip drug maker Krka were again the most traded, Ilirika said. Krka lost 4.3% to 65.24 euro on 1.82 million euro of turnover.
LJSE's total turnover more than doubled to 4.7 million euro on Friday from 2.17 million euro on Thursday, with the bond market contributing 1.84 million euro to the total turnover.
($=0.7928 euro)