Cantor introduces block trading & underwritten liquidity on prediction markets.

Cantor Fitzgerald is now brokering block trades on event contracts on Kalshi for its institutional clients, with Susquehanna providing the majority of liquidity. Cantor’s co-CEO and global head of equities stated it clearly: prediction markets are growing fast, but institutional participation hasn’t kept pace because investors have lacked the ability to transact at scale.

Kalshi spent years as a crowd-sourced order book venue. This new institutional product isn’t a deeper book, it’s negotiated block trades, brokered by an intermediary (Cantor) that understands both sides of the market, warehoused by a single professional balance sheet.

What it still fails to cover is the tail. The demand that Cantor & SIG describe is weather, commodities, and economic prints — standardized contracts a listed pipeline can keep liquid, listed on the venue’s own schedule. A public order book cannot write a bespoke contract against a single desk’s positions, nor price adverse selection on flow that isn’t identifiable.

For the reasons above, Martingale remains thesis-driven on OTC brokerage, keeping swaps desks alive next to futures exchanges. That’s what allows us to address single-name catalyst risk.

In our view, SIG has taken the liquidity warehousing seat for macro; tail events need a different structure.

This broker-arranged block model, which we suspect will propagate across the Street, bilaterally negotiates OTC-style block trades on standardized public contracts that undergo Kalshi’s internal liquidity screen; this fails on tail events. Martingale’s model negotiates the n-of-1 contract itself, with bespoke terms tailored to the institutional counterparty’s needs on events that evidently fail such liquidity screens. Martingale’s contracts are designed to be privately negotiated and not retail-fungible: there is no listed proposal, no public order book, no open interest to read, and no footprint on public markets that attributes the position to the institution that hedged it. Like any swap, they remain subject to regulatory reporting, which is anonymized.