Shares in the country's fourth-largest lender Kasikornbank Pcl inched up 2.24 percent to 160 baht, tracking gains in the broader banking index, and boosted by strong loan growth in May.
The banking index was up 0.19 percent at 0843 GMT.
Broker DBS Vickers said the banking sector, excluding Krung Thai Bank and CIMB Thai Bank, has seen good loan growth momentum in May -- up 1.2 percent from the previous month and 14.6 percent higher from the previous year.
The broker rated Kasikornbank as one of its two top picks in the sector, along with Bangkok Bank, with a better-than-expected expansion in corporate and small-to-medium enterprises (SME) loan growth.
"Kasikornbank is leading in SME clients with its strong asset quality, lowest non-performing loan ratio and highest net interest margin within the major banks," DBS Vickers said in a research note.
Kasikornbank's peer Bangkok Bank fell 1.1 percent at 180.50 baht, while the main Thai index fell 0.94 percent.
1541 (0841 GMT) (Reporting by Sinsiri Tiwutanond in Bangkok; email@example.com)