Bitcoin stormed above $45,000 on Tuesday for the first time since April 2022 as the world's biggest cryptocurrency started the New Year with a bang buoyed by optimism around possible approval of exchange-traded spot bitcoin funds.

Bitcoin touched a 21-month peak of $45,532, having gained 156% last year in its strongest yearly performance since 2020. It was last up 2.5% at $45,318 but remains far off the record high of $69,000 it touched in November 2021.

Ether, the coin linked to the ethereum blockchain network, was 1.45% higher at $2,386 on Tuesday, having surged 91% in 2023.

Investor focus has squarely been on whether the U.S. securities regulator will soon approve a spot bitcoin ETF, which would throw open the bitcoin market to millions more investors and draw billions in investments.

The U.S. Securities and Exchange Commission has rejected multiple applications to launch spot bitcoin ETFs in recent years, arguing that the cryptocurrency market is vulnerable to manipulation.

In recent months, however, there have been increasing signs that regulators are prepared to sign off on at least some of the 13 proposed spot bitcoin ETFs, with expectations that the decision will likely come in early January.

The reaction to a possible rejection would be clear cut and likely see an immediate tumble, said Chris Weston, head of research at Pepperstone.

"However, should we see the green light the obvious question is whether we get a buy the rumour, sell-on-fact scenario playout or whether it promotes another leg higher," he added in a note.

Rising bets that major central banks will cut interest rates this year has also been a boon for cryptocurrencies, helping shake off the gloom that had settled over crypto markets following the collapse of FTX and other crypto-business failures in 2022.

"The crypto market is set to experience notable growth this year, with key influencing factors being the influx of investment funds from spot ETFs, Bitcoin halving, and a more accommodative monetary policy both in the United States and worldwide," said Jupiter Zheng, partner of liquid funds at HashKey Capital.

(Reporting by Ankur Banerjee in Singapore and Summer Zhen in Hong Kong; Editing by Jacqueline Wong and Shri Navaratnam)