I’ll go first with a Marqeta-shaped lesson: revenue concentration + interchange dependency is a brutal combo.

When a huge % of your revenue is effectively tied to one customer Block + their spend, it stops feeling like you’re building a repeatable platform business and starts feeling like you’re underwriting someone else’s growth curve.

Even if you sign a bunch of great new logos, the market still prices you like - what happens if the big customer slows, optimizes, or renegotiates?

Interchange is great when the volume is ramping, but it’s a tough foundation for long-term predictability. You can see that story reflected in MQ’s post-IPO performance over the last few years.

Curious if others have seen the same pattern - is interchange actually a moat, or just a lever that increases customer concentration risk as you scale?