Report: AI Agent Completes Over $73 Million On-Chain Payments, USDC Becomes Default Settlement Asset

May 26: Crypto market maker Keyrock, in collaboration with Coinbase, Tempo, and Virtuals Protocol, released the report "Who Pays the Agent?" The report frames AI Agents as fast-growing core participants in the on-chain economy. Key data from May 2025 to April 2026: AI Agents completed roughly 176 million on-chain transactions, with total settlements exceeding $73 million. The average per-transaction value sits at just $0.31 to $0.48, marking the rise of a "machine-native micro-payment economy." About 76% of these payments fall below Visa’s $0.3 fixed fee threshold, meaning traditional bank cards and legacy payment systems can’t adapt to AI’s demand for high-frequency, low-value, autonomous transactions. Further stats show 98.6% of AI Agent payments settle in USDC. As of Q1 2026, over 104,000 AI Agents are registered. On the Base network, a USDC transfer costs roughly $0.0001—only 0.03% of that average $0.31 transaction—giving it a massive cost advantage over traditional payment systems. The report notes stablecoins are becoming the go-to currency infrastructure for AI and machine-to-machine economic activity. However, Keyrock warns that the AI payment ecosystem’s heavy reliance on USDC creates centralization risks: the entire emerging AI payment system depends heavily on the regulatory oversight and infrastructure stability of a single stablecoin issuer. Several tech and payment companies are building AI Agent payment infrastructure, including Coinbase’s x402 protocol, Stripe and Tempo’s Machine Payments Protocol (MPP), Google’s AP2 Delegated Payments System, and Visa’s expanded tokenized payment credential services. Finally, the report highlights a regulatory gap: current frameworks—like the EU’s MiCA, the U.S. GENIUS Act, and the EU AI Act—lack comprehensive standards for AI autonomous financial transactions and machine-to-machine payment behavior.