Delivery company FedEx says a recent cyber-attack cost its TNT division about $300m (£221m).
The company was one of several to have its computer systems severely disrupted by the NotPetya ransomware outbreak in June.
Company executives also acknowledged TNT had yet to fully restore all its IT operations and was expected to do so only at the end of the month.
And they said deliveries and sales continued to suffer as a result.
Other international companies have also taken sizeable financial hits as a result of the malware.
Shipping company Maersk announced in August that it had costed its damage at "up to $300m".
And consumer goods company Reckitt Benckiser warned the attack was likely to have cost it £110m.
The British company may provide an update on that figure when it issues its next earnings report, in October.
During a conference call with bank analysts, FedEx's chief information officer confirmed his company believed it had been exposed to the attack via an infected tax software update used by its Ukrainian office.
Rob Carter added he believed no customer data had been exposed as a consequence and the malware had not spread to FedEx's wider systems.
But he said TNT had lost business as a result of its struggle to recover.
"This was not an ordinary cyber-attack," said Mr Carter.
"This attack was the result of [a] nation state targeting Ukraine and companies that do business there.
"At the time of the attack, there was already work under way to replace TNT legacy systems with FedEx technology.
"In the wake of the attack, these efforts have been accelerated.
"The recovery and restorations of TNT Express's global operations and IT systems has... included every facility, hub and depot.
"Many systems that were not impacted by the virus were also fortified and rebuilt to ensure additional focus on security."
The BBC reported in August that TNT had had to resort to WhatsApp for internal communications as its email system had become inaccessible.
A source also disclosed its depots had been "pushed to their limit" and had found themselves with tens of thousands of unprocessed packages at the end of the day instead of the usual "handful".
But FedEx's chief operating officer defended the decision not to turn away business.
"Our operational teams remain focused on serving our customers and made a critical decision in the first 24 hours after the attack - keep our doors open for business, despite being reduced to manual processes for pick-up, sort and delivery," said Dave Bronczek.
"Our teams are [now] restoring customer volumes to our expected levels.
"This plan includes leveraging our senior officer team on sales calls to instil confidence with customers so that we can fully meet their expectations."