New agent protocols arrive with a sense of novelty. They define how software asks to pay, how a mandate is expressed, how a machine-to-machine transaction is shaped. It is easy to assume that a new protocol means a new system of money. It does not. Follow any of these flows to the end and it settles through the same core the financial system has used for decades: correspondent banking, local schemes and card networks. The protocol changes the asking; the clearing does not change.

The last mile is still correspondent banking

When value moves between institutions, it usually depends on correspondent relationships — accounts one bank holds with another so that payments can be cleared across borders. This is the layer beneath the protocols, and it has been thinning. The number of active correspondent banks worldwide fell by roughly 22% between 2011 and 2019, even as payment volumes rose. In Latin America, active relationships fell by around 30% since 2012.

The bottleneck

Fewer relationships, more volume. That combination concentrates risk and raises cost, particularly for corridors that are already hard to serve. Agent payments inherit this. A protocol can make a machine payment frictionless to request and still leave it queued behind a clearing layer that was not built for continuous, cross-border, small-value flow.

Why it matters for agents

Agentic commerce multiplies the number of cross-border operations, and each one ultimately needs a path to settlement. If the core cannot keep pace, the constraint moves from the agent to the infrastructure beneath it. Recognising this reframes the problem: the frontier is not another protocol on top, but a better way to connect the protocols to the rails and institutions that clear them. The protocols will keep multiplying; the settlement core they depend on will not.

In short

  • Agent protocols change how payment is requested, not how it clears.
  • Settlement still runs through correspondent banking and card rails.
  • Correspondent relationships have been thinning while volumes rose.
  • The bottleneck sits beneath the protocols, not within them.

For more background, see the blog.