A game of tennis may have handed Berlin to the far left party

Berlin elects its city parliament on September 20, and the party ahead is Die Linke, the far-left successor to East Germany's ruling communists. It has never governed the city. Two days ago its federal leader made the seizure of 260,000 flats from three corporate landlords a condition of joining any coalition.

It got there because the CDU fell apart. On January 3, an arson attack cut power to more than 40,000 Berlin households for up to four days, the city's longest outage since 1945. Governing Mayor Kai Wegner spent part of it playing tennis. His party confirmed him as its candidate with 93% on June 9, and he withdrew on July 10. Stefan Evers has had the job for four weeks, and the CDU's polling has not moved a point.

Polymarket's Berlin market now has Die Linke at 41 cents against the CDU's 25, the highest it has ever traded, on a day when no new poll was published. Die Linke leads the weighted average by only 1.3 points. Here's why we think Die Linke will win.

The contract pays on seats, and 78 of Berlin's roughly 130 seats are won in single-member districts on a simple plurality.

• The CDU took 48 of those 78 districts in 2023, but it did it on 28.2%, and nobody is polling near 28% now
• With five parties inside five points, a district can be won on a quarter of the vote
• That rewards concentration, and Die Linke's vote is concentrated in the eastern boroughs
• It was already the largest party in Berlin at the 2025 federal election on 19.9%, winning four districts outright, including Treptow-Köpenick on 41.8%
• In 2023, the SPD finished 53 list votes ahead of the Greens across the whole city, and both took exactly 34
• The Greens have lost 12 cents in a month, and their vote sits in Friedrichshain-Kreuzberg and Neukölln, the same inner-eastern districts Die Linke needs.