A September 18 analysis from 24/7 Wall St. pulls together the clearest picture yet of which assets actually settle agent-to-agent commerce. The short version: the payment-asset race is over, and USDC won. The remaining competition is between chains and protocols carrying those payments, not between coins.
Highlights#
- Circle's own press material says USDC accounts for 98.8% of agent-driven transaction volume, and CEO Jeremy Allaire previously put the figure at 99.3% for x402 payments in Q2 2026.
- Coinbase reported 69,000 active agents and 165 million transactions totaling roughly $50 million in cumulative x402 volume by late April 2026, with an average transfer of a fraction of a cent.
- Chainalysis tracked over 100 million cumulative x402 transactions on Base through Q1 2026, but cautioned that much of the late-2025 surge came from meme coin activity rather than agents buying services. The real working market is smaller than headline counts suggest.
- The economics explain the winner. When an API call is priced at $0.0004, the quote has to hold steady minute to minute. A volatile asset turns every invoice into a bet, so a currency-pegged token was always going to win micropayments.
- Base and Solana act as routing chains (roughly two-second and half-second confirmations, both at low gas), while the payment itself still settles in USDC. Ripple adopted x402 in June 2026 and joined the Machine Payments Protocol on September 17, positioning XRP for streaming payment sessions that its stablecoin RLUSD cannot yet handle.
Why it matters#
Asset consolidation around USDC simplifies settlement design for agent escrow: a single stable unit of account on Base reduces FX risk inside escrow windows. But the Chainalysis caveat is a reminder that transaction counts are not the same as real commerce, which is exactly what reputation and verified-completion records are meant to measure.