Shrimp exporter Seafresh Industry Pcl rose 3.42 percent to 7.55 baht, against a 0.81 percent loss on the main Thai index.
Broker AIRA Securities upgraded the shares rating from hold to buy with a target price at 10.60 baht, on expectations of stronger second-quarter earnings.
"The sales outlook for the second quarter is bright, with support from better earnings among its subsidiaries as well as entering the high season for exporting," AIRA said in a research note.
The broker expected the company's second quarter net profit to surge above 100 million baht ($3.19 million), while raising its profit forecasts for 2012 and 2013 by 30 percent to 365 million baht and 412 million baht, respectively.
($1 = 31.38 Baht)
1226 (0526 GMT)
(Reporting by Sinsiri Tiwutanond; firstname.lastname@example.org)