TLDR
- Kalshi handled $127.4 million in 11 midterm markets early on November 4, more than four times Polymarket’s $30.6 million.
- Polymarket still captured 51.5% of U.S. prediction-market search demand on Election Day, ahead of Kalshi’s 47.5%.
- In October, Kalshi ended Polymarket’s 29-month run as the search leader with a 51.8% share.
- Football combo bets made up 67.6% of Kalshi’s October volume, according to TokenPost data.
- The year’s biggest search spike came on March 2, shortly after the Iran war began.
Kalshi handled more than four times Polymarket’s trading volume in key midterm markets on November 4. Yet Polymarket drew more U.S. search interest that same day, according to new data from iGaming analytics firm Blask.
The split came one month after Kalshi ended Polymarket’s 29-month run as the top prediction-market brand in U.S. search demand. Blask said the midterms showed how fast consumer attention can move between the two platforms.
Election Day Trading vs. Search
According to Gaming America, Kalshi handled $127.4 million across 11 midterm markets between midnight and 6 a.m. ET on November 4. Polymarket handled $30.6 million in the same markets over that window.
That gave Kalshi about 81% of combined trading volume across the two platforms in those six hours. Democrats secured control of both chambers of Congress that day.
Search data showed a different result. Combined U.S. search demand for prediction-market brands rose to about four times October’s daily average, and Polymarket captured 51.5% of it.
Kalshi took 47.5% of that day’s search demand. It was still Kalshi’s strongest search day of 2026, Blask said.
Blask said the daily figures came directly from each company’s daily index values. It used the same method behind its monthly Brand Accumulated Power figures, which measure each brand’s share of total search demand among tracked rivals.
How Kalshi Took the Lead
In October, Kalshi held 51.8% of U.S. branded prediction-market search demand, compared with 37.5% for Polymarket. Kalshi’s Blask Index rose 153% from September, while Polymarket’s fell 3%.
The October numbers marked a sharp change from earlier periods. During the 2024 presidential election, Polymarket held 88% of branded search demand, while Kalshi had 8.5%.
In May 2026, Polymarket still held an 80% share against Kalshi’s 18%. Kalshi reached 36% in August before slipping to 29% in September.
Blask told Gambling Insider that Kalshi’s search demand actually grew about 14% in September. Its share fell because the total search pool expanded by about 41%, with Polymarket and Novig gaining ground.
Kalshi’s October rise lined up with a jump in sports trading. It recorded $19.03 billion in contract volume from October 5 to 11, with parlay-style combo contracts making up about 70%, according to Predictable data cited by Blask.
TokenPost data cited by Blask showed football combos made up 67.6% of Kalshi’s October volume. Blask said its football link is based on timing, not a breakdown of search queries.
Polymarket still led on some single days in October, including October 25 to 30. The November 4 surge ranked as the second-largest search day of 2026.
The largest came on March 2, when search demand was about 7% above the midterm peak. Polymarket held 87% of search demand that day, shortly after the Iran war began and one day before the first midterm primaries in Texas, North Carolina, and Arkansas.
Blask now sees the war as the stronger explanation for that spike, noting that four days between March 2 and 6 came close to the November 4 level. Super Bowl LX on February 8 produced the third-largest peak, with demand split almost evenly.
Blask said it is too early to say whether Kalshi’s October lead marks a lasting shift. The firm pointed to Kalshi’s gains before football season and its stronger search share during major U.S. events as signs of a broader change.
