USDC Dominates AI Agent Payments with 98.8% Share

The quiet battle for dominance in AI agent payments has been won by USDC, which accounts for 98.8% of agent-driven transaction volume.

This result was not accidental, as Circle introduced its Agent Stack in May 2026, providing developers with policy-controlled wallets and nanopayments.

The x402 standard, built on the HTTP 402 Payment Required response, is used for settling these transactions, with USDC being the chosen stablecoin due to its stability and ability to maintain a constant value.

Solana offers high-throughput routing, but it does not settle payments. XRP, which took longer to enter this arena, supports streaming payment sessions through its adoption of the x402 standard in June 2026.