Diane Lebouthillier, the federal Minister of National Revenue
In April 2016, when the Panama Papers were released, The Globe and Mail reported, "The [Canada Revenue Agency] says it wants hundreds of millions of dollars in back taxes from Cameco Corp., Silver Wheaton Corp. and Loblaw Cos. Ltd. because, the CRA says, the companies inappropriately ran international transactions through subsidiary companies in low-tax foreign jurisdictions. The three companies are contesting the allegations, which remain untested in court."
That Globe and Mail news article provides the background that, "Cameco's fight with the CRA began in 2008; the tax agency has now reviewed the company's tax returns from 2003 to 2010 and told Cameco it believes it has $3.4-billion more in Canadian income for those years than the company declared. Cameco says it expects CRA will add another $3.6-billion in taxable income for 2011 through 2015. The total tax bill for the 13 years: $2.1-billion, plus interest and penalties."