The chief executive of one the world’s largest cryptocurrency exchanges has called it quits. Chris Lee, the head of OKEx, has resigned from the Hong Kong-based exchange just as it was executing major international expansion plans and was on track to become the most widely-used cryptocurrency trading platform. OKEx did not immediately respond to a request for comment, but the company told Bloomberg in a statement that Lee had left for personal reasons, including the desire to “start a new life.”A spokeswoman for Lee further told the publication that he intended to take a break from his professional life to spend more time with his family, after which he would return to the blockchain community. It had been “the greatest pleasure and an honour” to lead OKEx, he said. Lee’s picture and biography are no longer featured on the firm’s website, and the company has not yet announced who will replace him as chief executive. OKEx — which operated under the name OKCoin when it was open in mainland China — has long been one of the world’s most popular cryptocurrency exchanges, and over the past several weeks it has surpassed Binance in daily trading volume to become the largest cryptocurrency trading platform. Over the past 24 hours, OKEx has processed $2.1 billion worth of trades, while Binance has facilitated $1.9 billion in volume, according to self-reported data aggregated by CoinMarketCap. Like Binance, which also has a major presence in Hong Kong, OKEx has begun a major expansion into the island nation of Malta, which has positioned itself as a low-regulation haven for major cryptocurrency firms. OKEx has also recently released its own utility token, and the firm has announced plans to build a public blockchain for the token as part of its effort to launch a full-fledged decentralized cryptocurrency exchange (DEX)