AI agents are about to rediscover the oldest risk in modern finance

On 26 June 1974, German regulators withdrew the banking license of Bankhaus Herstatt, a mid-sized bank in Cologne, in the middle of the trading day. The timing is what made it famous. Herstatt's FX counterparties had already irrevocably paid the Deutsche Mark legs of that day's trades in Frankfurt. The corresponding dollar legs were due to settle hours later in New York. They never did. Banks that had done nothing wrong except pay first were left holding losses on trades that were half-settled: one leg complete, one leg gone. The episode was significant enough to name a category of risk - settlement risk, still called Herstatt risk - and it pushed the G10 central banks to form the Basel Committee on Banking Supervision later that same year. Here is the part worth sitting with: the actual fix took 28 years. The fix was a central utility CLS launched in 2002 with one job: settle FX trades payment-versus-payment. Both legs of a trade settle simultaneously, or neither does. There is no window in which one side has paid and the other has not. It works - CLS settles on the order of trillions of dollars a day - and it is the reason a Herstatt-style failure has not repeated at scale in the currencies it covers. But look at the shape of the solution. To make two legs atomic, traditional finance built one institution that every major bank trusts, connected the world's main currencies to it, and routed the trades through it. Atomicity was achieved by adding the most systemically important middleman in the history of payments. That was probably the only option available to 1990s banking infrastructure. It is not the only option available now. The agent economy is still in its payments era A study published last week by Keyrock, run with Coinbase and Tempo, put numbers on machine-to-machine commerce: 176 million transactions, $73 million settled between May 2025 and April 2026, average transaction size around $0.31. Those numbers describe a payments economy. A payment is a singl