The Canadian firm, which employs 4,000 people in Belfast, has been slapped with a second preliminary levy of 80% on the exports of its planes to the US, the Trump administration announced on Friday.
Bombardier is already facing a 220% tariff on a new model of passenger jet as part of a separate investigation into claims from US firm Boeing (NYSE: BA - news) that it received unfair state subsidies from the UK and Canada.
The wings for the jet are made in Northern Ireland and Bombardier has said the C-Series model affected by the row is "critical" to its operations there.
Prime Minister Theresa May has lobbied President Donald Trump over the row, with Defence Secretary Sir Michael Fallon warning Boeing its actions could jeopardise future UK Government contracts.
Announcing the latest tariff, US commerce secretary Wilbur Ross said: "The United States is committed to free, fair and reciprocal trade with Canada, but this is not our idea of a properly functioning trading relationship.
"We will continue to verify the accuracy of this decision, while doing everything in our power to stand up for American companies and their workers."
Washington said its move was out of concern to prevent "injurious dumping" - exporting a product to a country at a lower price - of imports into the US, "establishing an opportunity to compete on a level playing field".
Bombardier did not provide the information requested, according to the Commerce Department.
It added: "The anti-dumping duty law provides US businesses and workers with a transparent, quasi-judicial, and internationally accepted mechanism to seek relief from the market-distorting effects caused by injurious dumping of imports into the United States."
Boeing alleges the unfair subsidy stems from when Northern Ireland's power-sharing administration and the UK Government pledged to invest nearly £135m to help set up a C-Series manufacturing site in Belfast.
The firm also took umbrage with Bombardier receiving $1bn (£765m) from the Canadian provincial government in Quebec in 2015, when its fortunes appeared to be flagging.
Boeing claims its complaint is a bid to seek a "level playing field" for global competitors, but Bombardier has accused its rival of hypocrisy.
Trade unions expect a final ruling on the pricing policy in February.