(Updated): Bitcoin’s price broke through $18,000 in what some experts are attributing to global events and bullish fundamentals in crypto.

The world’s top cryptocurrency by market capitalization reached a high of $18,062 at 03:01 UTC, a price point not seen since Dec. 16, 2017. After topping out at almost $18,500, prices dropped back below $18,000 for around two hours before crossing the level again.

Over the past 24 hours, bitcoin has ranged between $16,560 and $18,464.

Bitcoin is now up 146% on a year-to-date basis and has gained nearly 70% so far this quarter, according to CoinDesk 20 data.

“A few recent events have undoubtedly had an impact,” said Antoni Trenchev, co-founder and managing partner at crypto lender Nexo. “Institutional investment by the likes of MicroStrategy and Square, PayPal actively shilling crypto, and the bitcoin halving in May” were likely causes for bitcoin’s continual rise, he said.

Others see global events such as COVID-19 and negative interest rates in traditional markets, such as Germany, as the outliers for bitcoin’s meteoric rise this year.

“Interest rates are the most important factor in people’s decisions on where to deposit money,” said Ki Young Ju, CEO at analytics firm CryptoQuant. “I’m sure negative interest rates will drive adoption in crypto whether it’s direct purchasing crypto/index funds or using staking services.”

While bitcoin is fast approaching its Dec. 17, 2017 all-time high of $19,666, ether also broke new 2020 heights above $488 to stand at $489 by press time.

See also: Traders Brace for Major Volatility as Bitcoin Price Nears Record Highs

Another factor could be attributed to the easy money policies of central banks and increased government spending from some of the world’s largest economies including Europe and the U.S in recent months.

“I think it basically comes down to monetary and fiscal policy,” said Kyle Davies, co-founder of Three Arrows Capital.  “Central banks can lower rates until they get to slightly negative, and then they have to print money.”

At that point, Davies maintains, central banks’ dependency on newly printed money will make “BTC attractive.”