Iliana Yotova and Kiril Valchev lead with 33.8% in a parallel vote count by Gallup International Balkan, the agency said. The figures, shown on EuroNews, are based on 78% of the sample.
Gyurov and Kandev are second with 31.2%, according to Gallup International Balkan. Kostadinov and Volgin are third with 12.5%.
More on this story: Myara exit poll: Yotova and Valchev lead with 35.2%, Gyurov and Kandev on 32.2%
Radostin Vasilev and Krasimir Manov follow with 4.2%, Ivelin Mihaylov and Yuliana Mateeva have 3.4%, and Ivan Hristanov and Stoyanka Cherkezova have 2.2%.
Turnout is 22.4%, the agency said.
Updated (25.10, 23:22): Gallup International Balkan says its sample is now 100% complete, not 78%, and turnout is 23.1%, not the 22.4% first reported, BTA says. Iotova and Valchev have 34.1%, Gyurov and Kandev 32.3%, and Kostadinov and Volgin 12.7%. Radostin Vasilev and Krasimir Manov get 4.1%, Ivan Hristanov and Stoyanka Cherkezova 2.5%, and Ivaylo Simeonov and Kosyo Stoychev 1.4%. Other candidates, each under 2%, together get 4.7%, while 4.8% back no one.