It would be the most seats ever won by a single party in Latvia's parliamentary history.
With over 99 percent of votes counted, it had more than 35 percent.
The previous record was 36 seats, won by Latvia's Way in 1993.
Right-wing populist Latvia First came second with more than 13 percent and the Sovereign Power/New Latvians alliance was third with almost 12 percent.
Kulbergs said the result showed that voters wanted change.
Turnout was just under 52 percent, the lowest in any Latvian parliamentary election.
In 2022, the United List won about 11 percent and 15 seats.
The alliance will be the largest party in the new parliament.
The United List said it wanted to begin coalition talks with its current partners.
(ał)
Source: IAR