In this month's IRS Information Reporting Advisory Committee Public Report, they dive into the topic of collection of cryptocurrency taxes, citing research conducted by Fundstrat:

"...estimated cryptocurrency-related U.S. tax liabilities at $25 billion. That is based on approximately $92 billion of taxable gains for U.S. cryptocurrency investors, who, according to Fundstrat, comprise around 30 percent of cryptocurrency investors worldwide. Globally, the cryptocurrency market grew from about $19 billion at the start of January 2017 to more than $500 billion at the end of December 2017, according to data from CoinMarketCap"

Also in the report, their estimate that up to 50% of people could attempt to not properly report their cryptocurrency earnings, adding:

"Because transactions in virtual currencies can be difficult to trace and have an inherently pseudoanonymous aspect, some taxpayers may be tempted to hide taxable income from the IRS."

The full report can be viewed on the IRS website here.

Being called the "J5" for short - America, the U.K., Canada, Australia, and the Netherlands are teaming up to form an International Task Force called "Joint Chiefs of Global Tax Enforcement" with the goal of sharing intelligence to track down tax cheaters.

Their specific targets - tax evidaders using offshore accounts, and cryptocurrencies.

"The unique thing about the J5 is the operational collaboration between five countries on tackling professional enablers that facilitate offshore tax crime, cybercrime and the threat of cryptocurrencies to tax administrations, as well as making best use of internationally available data and technology.” said Hans van der Vlist, General Director of FIOD.

More news on this will come "late 2018" according to a press release from the IRS.

Full information can be found at http://www.irs.gov/J5