The Globe and Mail reports in its Friday edition that ADF Group, a Canadian maker and designer of complex steel structures, saw its stock market value crash after it warned of lower sales and profit in coming months as U.S. tariffs drive up its business costs and undermine the certainty it needs to clinch new orders. The Globe's Nicolas Van Praet writes that the Terrebonne, Que., company, which manufactured the steel structure and spire for the One World Trade Center tower in New York among other projects, reported growth in both revenue and earnings for its latest fiscal year ended Jan. 31. But it said those positive results are now overshadowed by the fallout from U.S. President Donald Trump's unpredictable trade policy. "We know what we know today but we can't attest for what's going to happen in the coming days, in the coming weeks and in the coming months and that's the challenge," ADF chief financial officer Jean-François Boursier said on a conference call. "All of this changes on a whim." Hundreds of Canadian companies doing business in the U.S. face the nearly impossible task of planning for a business climate whose rules seem to change day-to-day. ADF shares closed Thursday at $5.22, down $2.39 in Toronto.