That means the nearly 300 percent crippling duty imposed by the U.S. Department of Commerce will not be applied.
Bombardier on Friday called the decision a "victory" for "the rule of law".
A spokesperson for Boeing said it was "disappointed" by the ITC's decision and that it would "review the detailed conclusions when they are released".
Boeing says those funds allowed Bombardier to sell its new C Series airliner to Delta Air Lines at "absurdly low prices" in violation of USA trade rules.
Airbus acquired a majority stake in Bombardier's CSeries program in October with plans to assemble the plane in the U.S.in order to avoid import duties.More news: De Bruyne Comments On Sanchez Snubbing Man City For Man Utd
Boeing said it would "continue to document any harm to Boeing and our extensive USA supply chain that results from illegal subsidies and dumped pricing".
But the ITC on Friday nullified that decision on a 4-0 vote, ruling that a USA industry would not be "materially injured or threatened with material injury" by imports of the Bombardier planes.
Delta's position goes a little further: at the time of the tenure, Boeing just offered second-hand Embraer 190s. Even one government official said it wouldn't be surprised by a loss. Members of the trade panel didn't explain their votes but will do so in a report to be made public by March 2.
The 4-0 decision effectively blocks US President Donald Trump's plan to put a 292 percent tariff on Bombardier imports into the United States.
Boeing had won a ruling in the USA that resulted in the imposition of the tariff on Bombardier's jets, which were built for a number of U.S. airlines.
The Canadian government has already retaliated against Boeing.More news: How 50 Cent Accidentally Became a Bitcoin millionaire
Bombardier shares jumped more than 15% after the ruling.
But the C Series has struggled in the cutthroat narrow-body market, where Boeing and Airbus sell most of their planes.
The Canadian government told the commission that it can't side with Boeing's "unprecedented" argument because there is no evidence that any C Series planes will be imported into the United States because the planes destined for USA customers will be assembled in Alabama. "The USITC ruling means that good-paying Bombardier jobs can stay in Canada". Meanwhile, Boeing shares were trading slightly lower. "With this matter behind us, we look forward to delivering the C-Series to the United States market so that American airlines and the public can enjoy the many benefits of this remarkable aircraft".
"We always believed that the C Series, in order to reach its full potential, would need a very strategic partner and we do have a strategic partner in Airbus", he said.
Immediately following the ruling Airbus tweeted: "We are happy to see that the ITC concurred with our views".More news: Justice Department Threatens LA, California, Other 'Sanctuary' Jurisdictions With Subpoenas
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