Brokerage distribution helped push Kalshi to 96% of non-sports prediction market volume

A week holds 168 hours, and the contracts at the top of Webull's prediction markets page open and settle inside sixty minutes ^[9][10]. A dollar that rolls into a fresh contract at every settlement prints 168 dollars of reported notional. So Kalshi's $9.6 billion week ^[2] is consistent with about $57 million of trader balance at one end of the range and $9.6 billion at the other, where each position settles once ^[4]. A contract resolving in November on a Fed decision locks the money up for weeks and reports a single time. It lands in the same chart ^[11].

The two disclosed figures do not quite reach the round number. Kalshi's $9.6 billion plus Polymarket's $344.2 million is $9.94 billion ^[2][3][1]. Kalshi is 96.5% of that pair, or about 28 dollars of notional for every one of Polymarket's ^[2][3].

The non-sports column carries some sports. A multi-leg combo that bundles several sports legs settles as a single contract, the categorisation follows the contract instead of the legs inside it, and the full notional shows up outside sports ^[12].

Artemis reads onchain activity, and Polymarket's CFTC-regulated US venue does not settle that way, so whatever trades there is not inside the $344.2 million ^[13]. Other platforms split crypto contracts, combos and exotics by their own rules, and Cryptopolitan reports that the same week therefore produces noticeably different market share depending on where you read it ^[14]. The same report holds that every tracker agrees on the direction of travel and they disagree on the size of the lead ^[15].

Distribution explains the share to the extent the shelf is stocked with hourly contracts. Robinhood, Coinbase, Webull and Moomoo all carry Kalshi's contracts to a user base that never went looking for Kalshi ^[6], and Polymarket does not have those mainstream channels ^[7]. What the brokerages merchandise under non-sports is mostly short-dated crypto and index markets ^[8].

That leaves the lead dependent on a reseller with plans of its own. Robinhood supplies roughly a third of Kalshi's daily flow ^[17]. It is also building Rothera, an exchange and clearing venture with Susquehanna International Group that would let it list event contracts without a third party in the middle ^[16]. In my view the 96% measures who owns the app more than who owns the trader. The counter-thesis is that Kalshi's regulatory footing and market range would keep the flow even after Robinhood lists contracts itself. Two results would break the first reading: a tracker that counts Polymarket's regulated US flow and still puts Kalshi near 96%, and Rothera going live without denting Kalshi's daily volume.