The SBITOP closed 0.25% lower at 584.89 points after rising 0.16% on Wednesday.
Two of the seven blue chips of the Ljubljana Stock Exchange (LJSE) closed lower, two rose and three closed flat.
Retailer Mercator [LJE:MELR] led the blue-chip decliners, falling 1.68% to 114.05 euro ($148).
Energy company Petrol [LJE:PETG] paced the blue-chip gainers, rising 0.45% to 213.95.
Insurer Zavarovalnica Triglav [LJE:ZVTG] was the most traded blue chip with 5,993 shares changing hands.
LJSE's total turnover rose to 1.7 million euro from 1.1 million euro on Wednesday.
($=0.7699 euro)