Apple may find itself on the hook for a huge tax bill in Europe. The iPhone maker could owe more than $8 billion in back taxes if a European Commission investigation rules against it and its tax practices within the economic region, Bloomberg Intelligence reported.

The issue at the center of it all is Apple’s subsidiaries in Ireland, which regulators accuse the company of using to reduce its tax bill on overseas revenue significantly. The European Commission opened its investigation into the company’s tax arrangement in Ireland in 2014.

Apple pays a foreign tax rate of only about 1.8 percent while earning about 55 percent of its total revenue outside the United States, according to the Bloomberg analysis. But if the commission rules its accounting practices violate EU rules, Apple could be on the hook for a 12.5 percent tax on $65.1 billion in profit made from 2004 to 2012.

While Apple is in the spotlight of this investigation, the European Commission was also simultaneously investigating tax arrangements that Starbucks made with the Netherlands as well as a deal Fiat made with Luxembourg. In October 2015, both companies’ tax arrangements were found to be illegal under European Union state aid rules.

The ruling regarding Apple’s accounting policies isn’t expected until March. However, Apple is expected to appeal any adverse decision.

Apple listed the European Commission investigation as one of the potential risk factors for the company in its annual regulatory filing with the Securities and Exchange Commission in October.

CEO Tim Cook has denied the company isn’t paying its fair share of taxes. “That’s total political crap,” Cook said in an interview with “ 60 Minutes” in December when asked about congressional criticism of its overseas tax policies.

Apple is expected to report its 2015 fiscal first quarter earnings Jan. 26 after markets close, followed by a conference call at 2 p.m. PST/ 5 p.m. EST.