Iliana Iotova and Kiril Valchev lead a national poll by Market Links ahead of the presidential election, with 47.3%. Andrey Gyurov and Georgi Kandev are second with 30.6%, a gap of 16.7 percentage points.
Market Links says no pair will win more than half the votes, so it expects a runoff between the top two.
Kostadin Kostadinov and Petar Volgin are third with 10.3%, twice the support for Vazrazhdane. All other pairs are below 5%.
Turnout in the first round is forecast at between 37% and 41%. At that level, Iotova and Valchev would get just under half of the votes cast. The poll says that if fewer than half of voters take part, the Constitution requires a runoff.
The "I don't support anyone" option on the ballot was chosen by 3.8% of those who voted. These votes are not counted in the candidates' shares.
Prime minister Rumen Radev is the only political leader with a nominally positive net rating. His rating has fallen every month since May, from +34 points then to +1 in October.
After five months in office, the cabinet has more distrust than trust: 41% against 36%. In September the result was balanced, and its net rating has since fallen by a further 4 points. Pollsters see trust in the cabinet as the main indicator of how well a government is doing.
Trust in parliament is 18%, the same as last month. Distrust keeps rising: it was 51% in July, 58% in September and is now 64%.
Trust in Kostadinov is relatively high and goes beyond support for Vazrazhdane. Market Links says this points to his majoritarian potential. The net rating of Radan Kanev and Asen Vasilev is around -50 points.
Trust in GERB leader Boyko Borisov is close to that in Democratic Bulgaria co-chairs Ivaylo Mirchev and Bozhidar Bozhanov. Distrust of Borisov is 79%, while distrust of the two co-chairs is markedly different. Delyan Peevski has the lowest net rating, -85 points, because distrust of him is the highest.
For 68% of those polled, the attack on merchant ships in the Black Sea is a very serious threat to national security. Another 17% are in the middle of the scale, and 15% think the risks are exaggerated.
More than a quarter of those polled think Ukraine is behind the attack, but Market Links says opinions on who did it point more towards Russia.
The national poll was held from 13 to 19 October among 1,006 people over 18, through face-to-face interviews and an online survey. Market Links paid for it and ran it together with a media partner.