Are certain cryptocurrency exchanges foreign accounts?
That's not a philosophical musing.
Americans who hold more than a certain amount of money abroad typically have to file reports with both the Internal Revenue Service and the U.S. Treasury. Failure to do so can result in more than $100,000 in fines and time in prison.
"U.S. taxpayers may not even be aware of this requirement because it's not something they readily file every year," said Selva Ozelli, a certified public accountant and lawyer who specializes in the digital coins.
Here are the rules: Anyone with more than $10,000 abroad usually needs to fill out the Report of Foreign Bank and Financial Accounts, or FBAR, with the Treasury Department each year. Another law — the Foreign Account Tax Compliance Act, or FATCA — requires certain U.S. taxpayers to describe their overseas accounts on Form 8938, when they file their taxes with the IRS.
But there is some uncertainty among tax professionals about whether cryptocurrency investors who buy off foreign exchanges need to go through these additional foreign account reporting measures.
"There probably is an FBAR requirement, but I wouldn't go as far as to say there always is one," said Kevin F. Sweeney, a former federal tax prosecutor and an attorney at Chamberlain Hrdlicka in Philadelphia.
He said a lack of guidance from the government has left a "black hole" in his analysis.
"It would seem awfully unfair if they would expect taxpayers to know that — and to then issue penalties for taxpayers who didn't do that — when practitioners can't even 100 percent figure out if there's an FBAR requirement," he said.
Indeed, there's been no direct information from the IRS on whether taxpayers who invest in the digital tokens need to fill out Form 8938, which gets attached to their 1040 each year.
The American Institute of Certified Public Accountants has written to the IRS, asking the agency for further guidance on foreign reporting requirements.
Both the IRS and the Treasury Department did not respond to CNBC requests for clarification.
When it comes to the FBAR, Ozelli said recent case law found that foreign online gambling accounts did come with such reporting requirements, suggesting that cryptocurrency exchanges do as well.
"If you're using foreign exchanges, it's going to qualify as a foreign reportable account for FBAR," Ozelli said.
And many cryptocurrency investors, she added, will find themselves in this situation. "A lot of the transactions still take place on foreign cryptocurrency exchanges," she said.
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Despite the ambiguity about the foreign reporting requirements, most tax professionals suggest erring on the side of caution.
"There is no set answer, but it never hurts to report," said Daniel Morris, an accountant with expertise in digital currencies.
It's risky not to, he said: "8938 is the only tax form that if you fail to file, and it's deemed that you should have filed, it's a potential felony."