The price of Bitcoin, the most popular digital crytpo-currency, has skyrocketed this year.

According to Coindesk, bitcoins are currently trading for $2,483 per coin. The price is an all-time record, and the remarkable valuation blows earlier price spikes out of the water. Bitcoins have more than doubled since the beginning of 2017, when they hovered around $1,000 per coin. Bitcoin broke the $2,000-per-coin barrier on Saturday.

The run-up has led to increased interest in lesser-known digital currencies, like Etherium and Ripple. Ethereum, which is backed by large companies working on blockchain projects, has jumped in value from $8.24 at the beginning of the year to $203.30, according to CNBC. Ethereum prices began climbing in March, around the time when Bitcoin investors started "getting jittery" about whether Bitcoin software would be able to handle the increased level of transactions. Looking at the market capitalization for all cryptocurrencies, Techcrunch notes that Bitcoin now makes up just 47 percent of the total market value.

Guessing what's behind the price increase is inevitably speculative. CBS news quotes market watchers who think digital currency value is being pushed up by economic instability in places like Russia, Nigeria, and South Korea. At Fortune, Jeff John Roberts argues that the mainstreaming of Bitcoin means that "investors see it as a new asset class" and are backing hedge funds to acquire it. Regulators in Japan and China have taken steps recently to formalize trading in Bitcoins, which has increased investment from Asia.

Price run-ups like this lead to "if only" type of thinking. Marketwatch published one portfolio manager's "regret" chart, showing that an investment of $1,000 USD in Bitcoin in July 2010 would be worth more than $35 million today. A $1,000 investment in a fund tied to the S&P 500 index would be worth around $2,500.

The price of Bitcoin has been highly volatile over the years, and it hasn't just moved in one direction. Bitcoins jumped to nearly $1,000 each in late 2013, but then plummeted in value, taking more than three years to rise back to that price point. 2017 is certainly a heady year for Bitcoin fans, but whether the crypto-currency gains widespread acceptance or ends up more like the 17th century Dutch tulip bubble, remains to be seen.