Hackers have stolen $60 million worth of digital coins from Tech Bureau Corp.’s Japanese cryptocurrency exchange Zaif, according to documents seen by Reuters.

The theft of Bitcoin (BTC), Monacoin (MONA) and Bitcoin Cash (BCH) occurred during a two-hour time frame on September 14. Three days later, Zaif began experiencing server issues, and upon investigation, became aware of the hack.

Of the amount stolen, nearly $20 million belonged to Tech Bureau, while the remaining $40 million belonged to clients of the exchange. Although a deal is still pending, Tech Bureau is working towards gaining an investment to pay back affected customers.

In response to the hacking event, the Financial Services Agency (FSA) of Japan is planning an investigation to determine if Tech Bureau will be able to cover Zaif’s customer losses.

Digital currency exchanges have suffered at least five major hacks this year, which leave professional money managers steering clear of the market despite individual investors piling in.

Japanese exchanges have suffered multiple hacks over the years. The high-profile Mt. Gox hack that occurred in 2014 and resulted in the exchange filing for bankruptcy, still looms as customers continue to wait for the return of their funds.

More recently, Bitcoin exchange Coincheck was robbed $530 million, which generated scrutiny toward the FSA, as findings regarding exchanges lacking proper security measure and protection against money laundering began to crystallize. Now, exchanges are required to register with the FSA before launching.

This latest hack may have long-term implications for how the FSA handles the digital asset industry as the government continues reviewing potential regulations.

More: Japan hit by another cryptocurrency heist, $60 million stolen
Interesting: Hackers Steal $200,000 in Cryptocurrency From ‘League of Legends’ Star