The value of the cryptocurrency market could almost double to $5 trillion by the end of the year, propelled by the January approval of spot bitcoin exchange-traded funds in the U.S. and the mining-reward halving due later this month, according to Ripple CEO Brad Garlinghouse.

“I’m very optimistic. I think the macro trends, the big picture things like the ETFs, they’re driving, for the first time, real institutional money,” Garlinghouse said in an interview with CNBC. “You’re seeing that drives demand, and at the same time demand is increasing, supply is decreasing,” said Garlinghouse.

The rate at which new bitcoin (BTC) are produced will be reduced after the reward halving, scheduled for April 20. That event, which takes place roughly every four years, has historically preceded a bull market for the largest cryptocurrency by market value. It lowers the number of bitcoin that miners are awarded for approving blocks to be added to the blockchain by 50%. This month's cut will take the payment to 3.125 BTC per block.

The crypto market is currently valued at around $2.68 trillion. Bitcoin has gained 63% since the start of the year and recently reached record highs above $73,000. The CoinDesk 20 Index, a measure of the broader crypto market, has rallied 49% in the same period.

Despite multiple regulatory crackdowns in the U.S., Garlinghouse said he remains positive on the future of crypto regulation in the country. Last June, the Securities and Exchange Commission (SEC) sued crypto exchanges Coinbase (COIN) and Binance, alleging they listed and traded unregistered securities in the form of various cryptocurrencies.

“One of the things actually I’ll say on the macro tailwinds for the industry: I think we will get more clarity in the United States,” he said. “The U.S. is still the largest economy in the world, and it’s unfortunately been one of the more hostile crypto markets. And I think that’s going to start to change, also.”

The SEC also filed a lawsuit against Ripple, a blockchain-based digital payment network, alleging it sold the (XRP) token illegally. Ripple denies the claims.