Japan's SoftBank Corp said it expected a gain of about 500 billion yen ($4.6 billion) from Alibaba Group Holding's share listing in New York, where the Chinese e-commerce leader surged 38 percent on its first day of trade.

SoftBank CEO Masayoshi Son also told CNBC that he would want to own more of Alibaba, although he reiterated that the Japanese mobile carrier and Internet media company was happy with the current 32 percent stake, which made it the Chinese company's biggest shareholder.

Asked if he would like more of Alibaba, Son told CNBC on Friday: "Of course."

Pressed on the likelihood of buying more shares, Son added: "Anything is possible but we are happy the way it is."

He said SoftBank considered Alibaba a core holding and he was upbeat about the Chinese company's future.

"My point of view is that this is the true beginning of Alibaba," he said. "I'm very, very optimistic."

SoftBank said in a statement on Saturday that it would book the estimated 500 billion yen gain in the half-year to end-September and would announce a precise figure at a later time. The gain was recorded to reflect Alibaba's increased asset value with the issuance of new shares and the conversion of preference shares to common stock in conjunction with the listing.

The Chinese e-commerce leader's shares surged in their Friday debut on the New York Stock Exchange as investors jumped at what is likely to rank as the largest IPO in history, betting on Chinese growth and a company that accounts for 80 percent of that country's online sales.