Four triggers could cause a huge cryptocurrency crash

 If it's true that the bigger they are, the harder they fall, then cryptocurrencies have been gearing up for a tremendous decline.But, then again, maybe this is just the start for the great crypto bull market.As of Monday, the entire cryptocurrency market stands at approximately $563 billion, according to industry site CoinMarketCap, which represents a more than 3,400 percent increase from the beginning of 2017.With some cryptocurrencies soaring several thousand percent, Google search results for the space coming in at all-time highs and lots of people hoping for overnight riches in nascent markets, it begs the question: Just how far can this growth be sustained and are we in a crypto currency bubble?I'm not going to argue whether or not the space is dangerously overinflated, but I am in the business of considering worst-case scenarios.My company, TenX, provides debit cards that people can use to spend their cryptocurrencies, so I want to always be prepared for whatever the future may bring. So here's the question I'm asking: If it is a bubble, then what could make it burst?Knowing that one person alone is hardly ever smart enough to weigh all the variables, I have set out over the past few weeks to talk to some of the brightest and most experienced people in the crypto ecosystem, to challenge them with the question of what could make a crypto bubble pop.Finding an obviously right answer was not so easy, but here are some ideas we came up with:

Regulation

If regulators in the U.S., Europe or elsewhere get together and ban exchanges and other companies that provide services to the crypto ecosystem, that would have a hefty effect on cryptocurrencies themselves, which cannot really be banned.Looking at China, which "banned" cryptocurrencies in the summer of 2017, there's one clear result: People and companies simply moved somewhere else. And instead of the market collapsing it rallied. Would the U.S. or Europe have a more dramatic effect? I am pretty sure they would, but how likely is the entire scenario of one of the major Western economies banning cryptocurrencies? After bouncing this idea off a lot of people that I trust, I would give it a 10 percent chance in 2018, leading to a decline of about 50 percent from the market top.

Exchanges

Prior to 2014, the crypto ecosystem saw one exchange accounting for over 70 percent of all trading volume: Mt. Gox. At the beginning of that year it suspended trading, initiating an 80 percent crash of the entire crypto market from its high.Some worry that we could see something similar today, but trading is much more distributed and hardly any exchange owns more than 10 percent of the entire trading volume according to CoinMarketCap. There are, however, some significant exchanges that do play an important role: According to Hackernoon, Coinbase and its backend solution GDax account for one of the largest exchanges to bring fresh fiat money into the ecosystem. It also boasts some of the largest user bases worldwide.So a problem to the ecosystem could arise not from a hack, but rather from the cessation of fresh money to keep feeding the growth.On the crypto-to-crypto side, we have an even scarier picture: One of the largest exchanges by trading volume is the only 6-month old exchange Binance, sometimes adding over 200,000 new users per hour.While I am NOT implying that any of the mentioned exchanges do a bad job, I am just highlighting some of the risks involved. What if Coinbase goes down and fresh money dries up? What if the extremely young exchange Binance runs into any issues?I know first-hand that they and many other exchanges do the best they can to keep users' funds safe, but there is always the risk of one or more of them blowing up. Growth is exponential and if some small thing goes wrong, it could make fresh capital dry up or lock up lots of coins indefinitely.I see the chances of a large exchange running into serious issues at around 25 percent for 2018 – with a drop of 10 to 15 percent from the market top.