American home improvement chain Home Depot may have seen one of the biggest data thefts in retail history, according to sources.

Credit and debit card numbers, thought to have been stolen between late April and early May, has appeared online seemingly coming from Home Depot. If so, it has been speculated that this could be one of the biggest data losses from a retailer ever seen, given the size of Home Depot’s store estate.

"I can confirm that we’re looking into some unusual activity and we are working with our banking partners and law enforcement to investigate," the company told The Register in a statement.