Bitcoin exhibited its trademark volatility Wednesday, plunging back toward $9,000 just hours after topping the $11,000 milestone for the first time.

A single bitcoin BTCUSD, -0.35% changed hands in recent action at $9,428.54, according to tracking site CoinDesk, a decline of 4.1% from Monday.

Earlier, bitcoin traded as high as $11,377.33. The move came just a day after the cryptocurrency hit $10,000 for the first time, adding to a rally that saw its year-to-date gains briefly exceed 1,000%. It’s still up sharply from its 2016 finish just below $1,000.

The fall came as Coinbase, one of the largest cryptocurrency exchanges, suffered a slowdown:

For many observers, bitcoin, and its accompanying volatility, have been a reason why they’ve labeled the cryptocurrency a market bubble.

“There are no fundamentals or technicals that explain this other than it being a massive speculative bubble. It’s hard to say precisely where we are in the curve, but the shape of the chart is parabolic and this sort of thing never, ever lasts,” said Neil Wilson, senior market analyst at ETX Capital, in a note.

Wednesday’s earlier rally marked the cryptocurrency’s fastest ever $1,000 jump. It took bitcoin just two days to reach the $9,000 mark, while it spent 17 days rallying from $7,000 to $8,000.

Ahead of Wednesday afternoon’s setback, analysts argued that momentum could carry bitcoin to further heights. Analysts have also noted that bitcoin has suffered larger selloffs over the course of the year.

“Given the huge demand the currency has, it could touch the level of $14,000 by the end of next year if not by midyear. Does that sound ridiculous? Well not really, when you are talking in terms of percentage points,” said Naeem Aslam, chief market analyst at Think Markets.

“From the 10K mark, if we project the price to $14,000, it is only 40%, and Bitcoin has the proven ability to move more than 50% in one month,” said Aslam in a Wednesday note.

Others are even more bullish on bitcoin. Michael Novogratz, a former Fortress hedge-fund manager, forecast on Monday that the cryptocurrency could soar to $40,000 by the end of 2018. He predicted there’s a “big wave of money coming, not just here but all around the world,” speaking in a CNBC interview.

The selloff may also underline concerns that traders are about to get severely burned if the bubble bursts. MarketWatch columnist Mark Hulbert, for example, predicts there’s a more than 80% risk of a bitcoin crash, arguing that its “extraordinary price run-up far exceeds the threshold for when a crash becomes nearly certain.”

Others have likened the supercharged rally to the tulip bulp mania in the Netherlands in the 17th century, where the price of the new must-have flower soared before dramatically collapsing. It’s considered one of the first recorded speculative bubbles.

“At the height of its price, tulip bulbs were selling for the value of a large piece of land and [were] 10 times more [than] an annual income of a skilled worker. After its collapse, it cost as little as an onion,” said James Trescothick, senior global strategist at easyMarkets, in a report.

He noted, however, that a potential bitcoin crash won’t be as dramatic as the tulip incident.

“When the bitcoin bubble does finally bust — and it will like everything else eventually does — I for one cannot see it falling so low that it becomes worthless. Like the tulip mania, the real question many analysts are asking is what is bitcoin’s intrinsic value,” Trescothick said.

“It does have a purpose, which I feel more people will eventually use it for what it was designed to do, which should help hold its value,” he added.