It touched $64,285 early in the Asian day, its highest since late 2021, and was last 2% firmer for the session at $63,850. Bitcoin's record high is $68,999.99 set in November 2021.

The largest cryptocurrency by market value has gained 50% this year and most of the rise come in the last few weeks where trading volume has surged for U.S.-listed bitcoin funds.

Spot bitcoin exchange-traded funds were approved in the United States earlier this year. Their launch opened the way for new large investors and has re-ignited enthusiasm and momentum reminiscent of the run up to record levels in 2021.

"The flows are not drying up as investors feel more confident the higher price appears to go," said Markus Thielen, head of research at crypto analytics house 10x Research in Singapore.

Smaller rival ether has hitched a ride on speculation that it too may soon have exchange-traded funds driving inflows. It's up 50% year-to-date though at $3,490 on Monday stayed just shy of two-year highs made last week.

The rally has come in tandem with records tumbling on stock indexes from Japan's Nikkei (.N225) to the S&P 500 (.SPX) and tech-heavy Nasdaq (.IXIC) and with volatility gauges in equities (.VIX) and foreign exchange (.DBCVIX) turning lower.

"In a world where Nasdaq is making new all-time highs, crypto is going to perform well as bitcoin remains a high-volatility tech proxy and liquidity thermometer," said Brent Donnelly, trader and president at analysis firm Spectra Markets.

"We are back to a 2021-style market where everything goes up and everyone is having fun."