Courier company FedEx Corp said Monday the recent Petya cyberattack will “negatively impact” its revenue as the company struggles to recover from the consequences of the attack.

The company made this disclosure in its annual report on Form 10-K for fiscal year 2017 with the Securities and Exchange Commission. The filing includes additional information regarding the June 2017 cyberattack on the worldwide information systems of TNT Express B.V., the international express transportation, small-package ground delivery and freight transportation company FedEx acquired in May 2016.

Petya involved the spread of an information technology virus through a Ukrainian tax software product. According to FedEx, TNT operates in Ukraine and uses the software that was compromised, which allowed the virus to infiltrate TNT systems and encrypt its data.

As of the date of this press release, all TNT depots, hubs and facilities are operational and most TNT services are available, but customers are still experiencing widespread service and invoicing delays, and manual processes are being used to facilitate a significant portion of TNT operations and customer service functions, said FedEx.

The company said it cannot estimate when TNT services will be fully restored, and the financial impact will be “material.”

FedEx does not have cyber or other insurance in place that covers this attack, and has experienced loss of revenue due to decreased volumes at TNT and incremental costs associated with the implementation of contingency plans and the remediation of affected systems, the company stated.