Watchdog assessing McDonald's and Greggs IT failures
The payments watchdog is examining the tech outages that have caused chaos for a number of high-profile retail outlets over the last week.
Greggs became the fourth major firm to suffer IT issues, following problems at McDonald's, Tesco and Sainsbury's.
The Payments Systems Regulator (PSR) said it was reviewing the situation.
"The PSR is aware of the recent payment issues and is assessing their nature to determine whether any further action is needed," it said.
The PSR is the UK's economic regulator for payment systems, seeking to ensure they work well for those that use them.
If it identifies an issue with payments infrastructure resilience, it can pass the matter on to the Bank of England.
Such systems are firmly in the spotlight after a series of technical glitches which left customers unable to make purchases.
Sainsbury's could not fulfil most online grocery deliveries on Saturday due to issues with an overnight software update which also hit contactless payments in stores. Tesco was also forced to cancel a "small number" of orders.
The day before, McDonald's restaurants around the world were unable to take orders due to a "global technology system outage".
On Wednesday, bakery chain Greggs became the latest major retailer to see its IT systems fail in some stores.
As a result of the outages being so close together, experts have suggested they could be linked, for example via a common network or payments infrastructure provider.
Alan Stephenson-Brown, CEO of IT firm Evolve, said the fact there were several outages was also a "timely reminder that even large corporations aren't immune to IT troubles."
He said the retailers would have lost millions of pounds.
"This highlights that digital disruption is a principal risk for many retailers. Ensuring contingency planning is in place is vital," Mr Stephenson-Brown said.
Jamil Ahmed, an engineer at transaction firm Solace, said the potential for "disruptions and vulnerabilities" will grow as businesses rely more and more on digital transactions.
"The brick and mortar retail industry is facing a crossroads. Customers, accustomed to the constant uptime and reliability of online shopping, are demanding the same flawless digital experience from physical retailers," he said.