I'd imagine a bigger loss for MasterCard was the EU capping their interchange fees to 0.3% with a regulation in 2015. "At present, credit card interchange fees in the UK are typically around 0.85% per transaction" (https://www.theguardian.com/money/2015/jul/27/cap-on-card-fe...). After Brexit MasterCard will increase it to 1.5% (https://www.theguardian.com/money/2021/jan/25/mastercard-to-...) Loosing out on 0.55% fee on every transaction is significant at MasterCard's scale.

I agree that will have a bigger effect, and boo Brexit. But it's actually only transactions on EU shops by UK cards that face higher fees, which is a really small percentage of purchases. Definitely not every transaction.

I'm sure they'll raise the other fees later though. Probably just dipping their toes.

Even more reason to accelerate instant payment system rollouts to avoid private payment systems that charge interchange fees.

What instant payment systems? Are there actually viable competitors to Visa/MasterCard?