Encrypted payments are becoming the default choice for AI Agents, with a high concentration on a single stablecoin.

Keyrock's latest report provides several key data points—
Over the past year, AI Agents have completed more than 176 million transactions on the blockchain, with settlement amounts exceeding $73 million; about 76% of Agent payments are less than 30 cents; 98.6% of AI Agent payments are settled via USDC.
The logic is clear—
AI Agents are beginning to autonomously purchase data, cloud computing power, APIs, and AI inference resources, all of which are high-frequency, microtransaction scenarios. Traditional bank card systems simply can't handle this— a transaction of a few cents costs more in card fees than the transaction itself. On-chain stablecoin transfer costs only "a fraction of a cent."
Major players have already fully entered the space— Coinbase, Stripe, Google, and Visa are all deploying machine-to-machine payments. Among them, Coinbase's x402 protocol allows Agents to pay directly with USDC.
But that 98.6% figure is both a victory for Circle and a hidden industry concern—
USDC almost monopolizes the AI Agent payment layer, greatly strengthening Circle's position. However, the flip side of this coin is: the entire emerging machine economy is betting on a single stablecoin issuer.
If USDC were to encounter issues someday, the impact would not only hit the crypto market but also the entire nascent AI Agent economy.
Efficiency leads to centralization, and centralization brings risks. This is a hidden pitfall planted at the very start of the machine payment era.