The World Trade Organization's preliminary report on a European Union complaint about U.S. government subsidies to Boeing ...

The World Trade Organization’s preliminary report on a European Union complaint about U.S. government subsidies to Boeing won’t come out next week and will be delayed until September.

WTO judges were tentatively set to release their confidential ruling to the U.S. and the EU on July 16. Nefeterius McPherson, a spokeswoman for the U.S. Trade Representative’s Office in Washington, said the confidential report is now scheduled to be issued in September.

“We can confirm that the chairman has spoken to the parties and has informed them that due to the complexity of the case, there will be a delay in the issuance of the interim report,” Keith Rockwell, the WTO’s spokesman in Geneva, said Thursday.

In a ruling made public last week, the WTO found that Airbus benefited from illegal European government subsidies for aircraft development. Boeing called the WTO ruling a “sweeping legal victory.”

Airbus Chief Executive Officer Tom Enders said the European plane maker is “surprised and disappointed” by the delay of the WTO report.

“We have said time and again that the complexity, interconnectedness and industrial significance of the Boeing and Airbus cases would strain the capabilities of the WTO,” Enders said in an e-mailed statement. When the report comes “it will show Boeing has received billions of dollars in WTO illegal subsidies,” he said.