The current bullish sentiment in bitcoin comes from riding a wave of crypto investor optimism surrounding the U.S. Securities and Exchange Commission’s approval of 11 spot bitcoin exchange-traded funds, or ETFs, in mid-January.

More than $577 million flowed into spot bitcoin ETFs yesterday alone.

Spot bitcoin ETFs allow for the institutional trading of bitcoin at its spot, or current, price. Previous bitcoin ETFs could only trade bitcoin futures. Futures are complex derivative instruments suitable for trading only by experienced investors.

In the wake of the SEC’s approval of the first U.S. spot bitcoin ETFs, the world’s oldest cryptocurrency has been on a tear, rising more than 42% year-to-date and jumping from under $50,000 at the time of approval to more than $60,000 today.