In a Sunday macro note framed explicitly as a thought exercise, Citrini Research modeled a speculative scenario in which AI-driven commerce structurally undermines card network economics.

Interchange in the Crosshairs

The central payments argument: AI agents optimizing consumer transactions around the clock would eventually identify the 2-3% card interchange rate as an obvious cost to eliminate. “Once agents controlled the transaction, they went looking for bigger paperclips,” wrote Citrini.

In the scenario, agents migrate toward stablecoin settlement on Solana or Ethereum Layer 2 networks, where transaction costs are “measured in fractions of a penny.”

Mastercard’s Stablecoin Positioning

Against this backdrop, Mastercard Incorporated (NYSE:MA) has been ramping its stablecoin infrastructure — a move the thought exercise suggests could prove prescient.

The note constructs a hypothetical first-quarter of 2027 Mastercard earnings headline showing purchase volume growth slowing to 3.4% year-over-year from 5.9%, with management citing “agent-led price optimization.” In the scenario, MA drops 9% the following session, while Visa Inc. (NYSE:V) partially recovers on perceived stronger stablecoin positioning.

Banks Face Compounded Risk

Citrini flags card-focused banks as carrying the sharpest exposure. American Express Company (NYSE:AXP), Synchrony Financial (NYSE:SYF), Capital One Financial Corporation (NYSE:COF) and Discover Financial Services each appear in the scenario as falling more than 10%, hit by both white-collar job losses gutting their customer base and interchange bypass gutting revenue. “Their moats were made of friction,” the authors wrote. “And friction was going to zero.”

“The sole intent of this piece is modeling a scenario that’s been relatively underexplored,” the authors wrote.

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