As the next bitcoin halving quickly approaches, Bitfinex CTO and Tether CEO Paolo Ardoino says its effect on price could be hard to predict as spot bitcoin exchange-traded funds increase the demand. 

During an online event hosted by Bitfinex on Friday, Ardoino was asked how the upcoming bitcoin halving event could affect prices, which he said could be hard to predict. 

"Already today, the demand of bitcoin is far outpacing existing mining," Ardoino said. "So we are seeing with these big institutions and the ETFs … the demand of bitcoin is far exceeding the current mining output. So sure, the mining output will reduce by half but that is a perception issue. The vast majority of the bitcoins have already been mined." 

While Bitfinex is no longer the dominant centralized …