2017 was a banner year for cryptocurrencies, but it could all be coming crashing down in 2018. For the second day in a row, the values of nearly all the top 100 cryptocurrencies are tumbling hard.

Just weeks ago, Bitcoin was trading for nearly $20,000. It's now selling for a lot closer to $11,000. Ethereum, which hit its all time high just days ago at $1,400+ per coin, is in a similar boat, now trading at less than $1,000. In fact, if you look at the graphs of almost any altcoin, you’ll see practically the same pattern. Everything tanked hard between January 15 and January 16. Some markets have stabilized and made a small recovery, but for the most part, if you have a cryptocurrency investment portfolio, you’re dealing with double-digit losses right now.

We’d be remiss to try and pinpoint the reason for the recent dive in cryptocurrency valuations. The world of crypto-trading is full of volatility, and crashes should be expected. However, it’s not every day that we see the entire market take a nose dive. Usually, while one currency is crashing, another up-and-coming token is flourishing, but this week everyone seems to be abandoning the digital currency markets.

The sudden change in investor sentiment is likely due to reports that authorities in South Korea and China are cracking down on cryptocurrency mining and trading. Last September, China started to scrutinize on cryptocurrency trading. Chinese authorities announced that the government considered the practice of fundraising through ICOs (initial coin offerings) illegal.

ICOs are to the cryptocurrency world what IPOs are to the investment world. When a new coin enters the market, its creators launch an ICO to sell the first round of coins to speculative investors. This raises money for the team that created the coin, which in theory would fund further development of the platform. And investors can get in at the lowest possible price and potentially secure high profits down the road. Unlike IPOs, which are heavily regulated and scrutinized by authorities, the ICO market is like the wild west. Regulations are few and far between, and practically anyone with a computer science background could launch a new coin, which makes investing in ICOs extremely risky. The upsides are high, but so are the risks. Investing in ICOs is a lot like gambling in that respect.

China also introduced new regulation that prompted the country’s largest cryptocurrency exchange to close its doors. Soon after China banned ICOs, South Korea banned the practice as well.

This week, China stepped up its efforts to curb the cryptocurrency markets with an announcement that it would block domestic access to platforms that enable crypto-trading. According to Bloomberg Technology, the Chinese government will also crack down on companies that provide “market-making, settlement, and clearing services for centralized trading.”

The South Korean government also played a pivotal role in this week’s crash. Last week, reports surfaced that suggested that South Korean authorities were preparing an all-out ban on cryptocurrency trading. On Monday, CNBC reported that South Korea’s Office for Government Policy Coordination clarified that a proposal to ban cryptocurrency trading is on the table, but a decision would not be made without “sufficient consultation and coordination of opinions.” The news instilled uncertainty in the cryptocurrency markets, and evidently, people began to panic.

For all we know, there could be several other factors that caused the sudden lack of trust in Bitcoin, Ethereum, and the like. Such is the nature of the cryptocurrency world. There’s no telling where the markets go from here, but something tells us we’re nowhere near the end for cryptocurrency. Just yesterday, Mark Cuban announced that the Dallas Maverick would accept Bitcoin, Ethereum, and “other tokens” as payment for next NBA season. 2018 is already shaping up to be another roller coaster year for cryptocurrency.