Weekly volume: Kalshi at $19B and Polymarket at $3.7B, both up about 85% on the week

Weekly volume rises sharply

Kalshi’s weekly volume reached $19B, while Polymarket’s stood at $3.7B, according to the supplied headline referencing Blockonomi. Both platforms were up about 85% on the week.

The figures put Kalshi ahead in reported weekly activity, even as the two platforms posted roughly matching percentage increases. Blockonomi’s page text was unavailable, limiting verification of the figures and their measurement methodology.

No fresh platform development

The accompanying update, published Oct 16, 2026 at 3:39 AM ET, reported no significant new platform headline during the preceding 15 minutes. The weekly volume figures therefore sit alongside a quiet immediate news window, rather than a newly reported platform development.

A Reuters $220M midterm study had also resurfaced in search. The update identified that item as a repeat and excluded it from the fresh-news assessment.

What it means for prediction markets

• Activity rose on both platforms: Reported weekly volume increased about 85% at both Kalshi and Polymarket, despite their different totals of $19B and $3.7B.
• Volume is not a probability signal: The supplied material contains no contract-level prices or positions, so it does not establish how expectations for any particular outcome changed.
• Freshness and methodology matter: The Reuters item was repeated reporting, while the unavailable Blockonomi text leaves the volume definitions and comparison basis unverified.