98.6% of AI Agent payment settlements are processed via USDC.

Article author, source: 0x9999in1, ME News

TL;DR

• Keyrock’s latest report (co-released with Coinbase, Tempo, and Virtuals) shows that from May 2025 to April 2026, AI agents executed over 176 million on-chain transactions, with a settlement value exceeding $73 million.
• 76% of AI Agent payment amounts are below $0.30—below the fixed fee floor of traditional card networks like Visa, making it physically impossible for traditional payment systems to accommodate them.
• USDC accounts for 98.6% of AI agent payment settlements, indicating extremely high concentration, making Circle the de facto "central bank of machine currency."
• As of April 2026, Coinbase's x402 protocol has processed approximately 165 million transactions, $50 million in transaction volume, and around 69,000 active agents.
• Google (AP2), Visa (tokenized credentials), Stripe (acquisition of Bridge), and Coinbase (x402) are simultaneously deploying their payment architectures in competition.
• Gartner predicts that AI agents will mediate $15 trillion in B2B procurement by 2028; McKinsey estimates global agent commerce will reach $3–5 trillion by 2030.
• MiCA, the GENIUS Act, and the EU AI Act will all take effect before August 2, 2026, but none cover machine-to-machine payments—creating a significant regulatory gap.
• Traditional financial giants have secured their position through acquisitions totaling over $8 billion (Capital One acquired Brex for $5.15 billion, Mastercard acquired BVNK for $1.8 billion, and Stripe acquired Bridge for $1.1 billion).

A transaction of 0.48 is rewriting the history of payments.

Let’s start with a number: $0.48.

This is the current average transaction amount for on-chain payments by AI agents. Less than half a dollar. Not enough to buy a cup of coffee.

But this small amount was repeated 176 million times over the past year, resulting in over $73 million in cumulative settlements—and not a single human pressed the "Confirm Payment" button.

On May 24, 2026, crypto market making and investment firm Keyrock, in collaboration with Coinbase, Tempo, and Virtuals, released a research report titled "Who Pays the Agent." The report’s central assertion is just one sentence:

Crypto rails are becoming the default payment layer for AI agents.

Not "could become." Not "may become in the future." It is "becoming." Present continuous.

This assessment is based on hard data: between May 2025 and April 2026, over 176 million on-chain transactions were executed by AI Agents through blockchain infrastructure, with a total settlement value exceeding $73 million.

You might say, what’s $73 million? Visa processes $14.5 trillion a year. Isn’t that a fraction of a fraction?

Correct. But the focus is not on scale. The focus is on the speed with which this infrastructure stack was formed, and the structural incapacity of traditional systems when faced with new demands.

Why can't my bank card be processed?

Let's look at a simple arithmetic problem.

In the traditional fee structures of Visa and Mastercard, there is a minimum fixed fee of approximately $0.30. Whether you swipe $1 or $100, this $0.30 is a rigid cost.

Now the question arises.

Keyrock's data shows that 76% of AI Agent payment amounts are below $0.30, with a high concentration of transactions in the "ultra-micro" range of $0.01 to $0.10.

You’re asking an AI agent to use a credit card to purchase a $0.03 API call? The fee is ten times higher than the transaction amount itself. This isn’t just “not worth it”—it’s physically impossible. It’s like using a semi-truck to deliver a letter.

The traditional card payment system was designed for humans. Humans make payments a few times a day. Human payment amounts start at least at a few dollars. Humans need to enter passwords, verify fingerprints, and wait for settlement.

But AI agents are different.

A trading agent may need to pay hundreds or even thousands of times per day for data sources, cloud computing power, and API inference services—each transaction costing just a few cents. It runs 24/7 without human authorization.

This is a completely new payment paradigm: high-frequency, ultra-small, fully automated, machine-to-machine.

The traditional banking system cannot handle any of these four characteristics.

Why a stablecoin? Why on-chain?

The answer is actually quite simple.

The cost of on-chain stablecoin transfers can be as low as a fraction of a cent. On high-performance L2s/L1s like Base and Solana, the gas fee for a single transfer is nearly negligible.

Compare:

• Traditional bank card: Fixed fee of $0.30 + variable rate (1.5%-3%)
• On-chain USDC transfers (e.g., on the Base network): less than $0.01

When your transaction amount is only $0.05, choosing which channel requires no thought.

Moreover, on-chain payments have a feature that traditional systems cannot achieve—programmability.

The agent does not need to "apply for an account." It does not need to "link a bank card." It does not need to "pass KYC." It only requires a wallet address and an authorization limit. Code is the contract. The contract is the rule. The rule is the execution.

This is why the x402 protocol developed by Coinbase has been adopted so rapidly.

x402: A 30-year-old payment easter egg hidden in the HTTP protocol

The design concept of x402 is extremely elegant.

The HTTP protocol includes a status code—402 Payment Required. This status code has existed since the 1990s but has never been officially implemented in the past thirty years.

Coinbase and Cloudflare activated it in May 2025.

The process is so simple it doesn’t need explanation: The AI Agent requests a paid API endpoint → the server responds with a 402 status code and pricing information → the Agent completes payment using USDC → retries the request with the payment proof → receives the data.

No human involvement required. No API keys needed. No subscription required. No billing backend needed.

As of April 2026, the x402 protocol has processed over 165 million transactions, with a total transaction volume of approximately $50 million and around 69,000 active agents. In December 2025, x402 V2 launched, supporting multi-chain and wallet sessions. In April 2026, Coinbase donated x402 to the Linux Foundation, establishing the x402 Foundation, with over 20 founding members including Google, Visa, Stripe, AWS, Mastercard, Circle, Microsoft, and Shopify.

In May 2026, Amazon AWS announced native integration of x402 into Amazon Bedrock AgentCore—the first time a major cloud provider has built crypto micropayments directly into an AI Agent infrastructure platform.

What does this speed mean? It means x402 is transitioning from "Coinbase's protocol" to "the industry's protocol." Once infrastructure standards establish network effects, the window for latecomers closes rapidly.

The Payment Stack Battle Among the Four Giants

Keyrock's report reveals a critically important competitive landscape: at least four complete AI Agent payment architectures are currently operational.

Coinbase: x402 + Base network + USDC

Cover five out of six layers of the payment stack. Native crypto pathways. Full-stack control from bottom to top.

Stripe: Bridge + Stablecoin Financial Account + Tempo Blockchain

In 2025, acquired the stablecoin infrastructure company Bridge for $1.1 billion and launched stablecoin financial accounts in 101 countries. Is integrating stablecoins as a "backend optimization layer" into existing payment systems.

Google: AP2 Protocol (Agent Payments Protocol)

An open protocol that allows users to delegate payment authorization to Agents via cryptographic mandates. Payment-agnostic—compatible with both on-chain and traditional card rails. Developed in collaboration with over 60 partners, including Mastercard, PayPal, and Coinbase.

Visa: Tokenized credentials + Nine Chain stablecoin settlement

Expand the existing card network to offer AI-ready tokenized payment credentials. The stablecoin settlement pilot has been extended to nine chains (Avalanche, Ethereum, Solana, Stellar, Arc, Base, Canton, Polygon, Tempo), with an annualized settlement volume of $7 billion, representing a 50%环比增长.

Keyrock's key finding is that Coinbase and Stripe each cover five out of the six layers of the payment stack, meaning they possess the most comprehensive vertical integration capabilities.

Traditional financial giants have not stood idly by. Over the past year, more than $8 billion in mergers and acquisitions have been completed in the industry: Capital One acquired Brex for $5.15 billion, Mastercard acquired BVNK for $1.8 billion, and Stripe acquired Bridge for $1.1 billion.

This is not a test. This is all-in.

98.6% concentration: Concerns behind the boom

One piece of data in the report is exciting, yet demands caution.

98.6% of AI Agent payment settlements are processed via USDC.

What does this mean?

This means Circle—the sole issuer of USDC—has effectively become the "central bank of the machine economy." Nearly all economic activity by AI agents runs on a single track, backed by one company’s single asset.

Is this a good thing? From an efficiency standpoint, yes. Unified standards reduce friction.

But from a risk perspective? This is a classic single point of failure risk.

If Circle encounters an issue—whether a technical failure, regulatory freeze, or reserve concerns—the entire payment infrastructure for the AI Agent could be paralyzed instantly.

More problematic is the regulatory vacuum.

Keyrock's report states that the EU's MiCA regulation, the U.S. GENIUS Act, and the EU AI Act will all officially enter enforcement phase by August 2, 2026. However, none of these three regulations cover machine-to-machine payment scenarios.

In other words: AI agents execute hundreds of thousands of autonomous transactions daily using stablecoins, but this activity currently exists in a complete legal gray area in every jurisdiction.

Who is responsible for payment failures by the Agent? Who covers the losses if an Agent is compromised and funds are stolen? Are autonomous commercial activities between Agents subject to taxation, and if so, how are taxes paid?

These questions have no answers today.

Trillion-dollar prophecy: bubble or beginning?

The numbers are overwhelming.

Gartner predicts: By 2028, 90% of B2B procurement will be mediated by AI agents, involving over $15 trillion in funds.

McKinsey estimates: By 2030, the global retail agentic commerce market will reach $3 trillion to $5 trillion.

In comparison, today's $73 million is indeed negligible.

But the issue is not today. The issue is the slope of the curve.

Watch the growth trajectory of x402: launched in May 2025 → processed over 100 million payments by December 2025 → reached 165 million payments, $50 million, and 69,000 active Agents by April 2026. From zero to one hundred million in less than a year.

Look again at Visa’s stablecoin settlement: annualized volume of $7 billion, up 50%环比增长50%。

AWS integrates x402 into its Agent infrastructure. Google releases AP2. Stripe rearchitects its payment system for the Agent economy.

All the giants are doing the same thing at once—this is no coincidence. It’s a collective vote on the future direction.

But I must say: going from 73 million to 15 trillion spans five orders of magnitude. This gap cannot be bridged by extrapolation alone. Along the way, there will be countless failures, bubble bursts, regulatory crackdowns, and technological bottlenecks.

Don't assume the path is smooth just because the direction is correct.

Core judgment: The infrastructure is in place; what's missing are the rules.

My view is clear:

First, the payment needs of AI agents are real, structural, and irreversible.

As AI agents continue to autonomously consume data, computing power, and inference services, the demand for high-frequency micropayments will keep growing. This is not dependent on the success or failure of any single project, but rather an inevitable outcome of the overall AI development paradigm.

Second, the crypto layer becoming the default payment layer is the result of an engineering choice, not an ideological victory.

It’s not because “decentralization is good,” but because on-chain payments have a decisive cost advantage in microtransaction scenarios. This is an economic issue, not a matter of belief. When your transaction amount is three cents, you won’t care whether the underlying technology is a blockchain or a spaceship—you only care whether the fee is low enough.

Third, the 98.6% concentration of USDC is a time bomb and also an entrepreneurial opportunity.

In the long term, the market will not tolerate single points of failure. USDT, PYUSD, and even future euro stablecoins will enter this space. Whoever establishes a second trusted settlement asset in agent payments will have found the next billion-dollar market.

Fourth, regulation is not a question of whether it will come, but of who will benefit once it arrives.

The implementation of MiCA and the GENIUS Act will bring short-term disruption to the industry, but will also eliminate participants with weak compliance capabilities. Players with licenses and institutional trust—such as Coinbase, Circle, and Stripe—are likely to become the biggest beneficiaries. Regulatory clarity often favors consolidation among market leaders.

Fifth, the winner of this payments stack battle is not who does it best, but who covers the most layers.

Keyrock's analysis points to a clear conclusion: the player with the most control layers will capture the largest share of value. Coinbase and Stripe, each controlling five layers, are moving toward a "full-stack monopoly." Their ultimate goal is not to build a protocol, but to become infrastructure operators for the machine economy.

In conclusion

Sometimes, the face of revolution is not earth-shattering.

Not a grand declaration. Not a groundbreaking product launch.

Just a $0.48 transfer. Completed silently. 176 million times. Not a single human present.

By the time you notice, the foundation of the entire payment world has already been replaced.

Bank cards will not disappear. Human payments will not disappear. But the growth of human payments is shrinking, while the growth of machine payments is exploding.

Whether it's Gartner's $15 trillion or McKinsey's $3 to $5 trillion, predictions can be questioned.

But one thing doesn’t require prediction: when machines start earning and spending money on their own, they won’t line up at banks to open accounts.

They will use stablecoins directly on-chain, within milliseconds.

This is what is happening.

Reference source

1. Keyrock, Coinbase, Tempo, Virtuals."Who Pays the Agent" research report. Published May 24, 2026. (Via CoinDesk reporting)
2. Bitcoin News. "76% of AI Agent Transactions Fall Below Visa's $0.30 Fee Floor." May 25, 2026. https://news.bitcoin.com/keyrock-report-76-of-ai-agent-transactions-fall-below-visas-0-30-fee-floor/
3. CryptoNews.net. "Crypto rails are becoming the default payment layer for AI agents, report says." May 24, 2026. https://cryptonews.net/news/finance/32911986/
4. Visa Investor Relations. "Visa Accelerates Stablecoin Momentum: Adding Five Blockchains for Settlement." April 29, 2026. https://investor.visa.com/news/news-details/2026/
5. Coinbase. "Introducing Amazon Bedrock AgentCore Payments, Powered by x402 and Coinbase." May 2026. https://www.coinbase.com/blog/introducing-amazon-bedrock-agentcore-payments-powered-by-x402-and-coinbase
6. McKinsey & Company. "The agentic commerce opportunity: How AI agents are ushering in a new era for consumers and merchants." October 17, 2025. https://www.mckinsey.com/capabilities/quantumblack/our-insights/the-agentic-commerce-opportunity-how-ai-agents-are-ushering-in-a-new-era-for-consumers-and-merchants
7. Gartner. "Strategic Predictions for 2026: How AI's Underestimated Influence Is Reshaping Business." 2026. https://www.gartner.com/en/articles/strategic-predictions-for-2026
8. ChainCatcher. "Report: Cryptocurrency is becoming the default payment layer for AI Agents, with 98.6% of transactions settled in USDC." May 24, 2026.