Eurohold jumped 6.43% to 1.49 levs, while Fibank added 1.83% to 4.44 levs, boosting the SOFIX by 0.82% to 863.01 points.
The two companies also buoyed the BGBX40, which tracks the 40 most traded shares on the Sofia bourse, and the BGTR30, in which companies with a free float of at least 10% have equal weight. Both indices were additionally lifted by a 1.24% increase in Central Cooperative Bank [BUL:CCB] to 1.63 levs.
Overall, the BGBX40 index went up 0.47% to 171.92 points, while the BGTR30 climbed 0.31% to 860.42 points.
The BEAMX index, which tracks the ten most highly capitalised growth companies, leapt 0.96% to 99.56 points on the back of a 28.80% surge in electric vehicle manufacturer Sin Cars Industry [BUL:SIN] to 0.492 levs.
Meanwhile, the BGREIT, which tracks seven real estate investment trusts, closed flat at 191.05 points as neither of the two constituents to trade posted any changes from Friday's close.
Total turnover on the main market of the Sofia bourse halved to 643,589 levs ($357,395/329,061 euro) on Monday from 1.34 million levs on Friday.
The highest turnover of the day, at 346,533 levs, was generated by diversified group Republic Holding [BUL:HREP] after 174,137 shares traded. The stock closed 0.50% lower at 1.99 levs.
(1 euro = 1.95583 levs)