Recently published data from the South Korean Financial Supervisory Service (FSS) shows that in 2017 several major South Korean banks have earned 2.2 bln won ($2 mln) in commissions from virtual accounts for cryptocurrency investing, a sum 36 times higher than the 61 mln won ($57,340) made the previous year, local news agency Yonhap reports.

The data on the banks’ income was gathered during an unprecedented financial probe conducted by the FSS and the Financial Intelligence Unit (FIU), first announced Jan. 7.

The probe inspected six major banks, Woori Bank, Kookmin Bank, Shinhan Bank, NongHyup Bank, Industrial Bank of Korea, and Korea Development Bank, to ensure that they were effectively preventing money laundering in their handling virtual accounts handling cryptocurrency.

According to Yonhap, The Industrial Bank of Korea reported 675 mln won ($634,500), with NongHyup Bank not far behind with a reported 654 mln won ($614,760).

Since last week, a wave of controversy has arisen in South Korea over the government’s attempts to more strictly regulate crypto markets, like the banning of the use of anonymous virtual accounts connected to crypto exchanges, forbidding underage citizens and foreigners to invest in crypto markets, and falsey announcing a total blanket ban on cryptocurrency trading.

On Jan. 16, a South Korean petition against the regulation of virtual currency reached over 200,000 signatures, now requiring an official response from the government.