SoftBank Group Chief Executive Masayoshi Son said on Tuesday he is a "heavy user" of ChatGPT, the artificial intelligence-powered chatbot from Microsoft-backed startup OpenAI.

"I am chatting with ChatGPT every day – I am a heavy user," Son told shareholders of the group's telecoms subsidiary.

Amid the excitement over AI, Son has stepped back from public pronouncements in recent months to focus on the planned listing of chip designer Arm as his technology investment conglomerate books heavy loss due to the sliding value of its portfolio.

Son also said he is speaking "almost every day" to OpenAI CEO Sam Altman, who made high-profile visits to Tokyo this year as he looks to capitalize on interest in generative AI and influence regulation of the burgeoning technology worldwide.

The San Francisco-based startup is supported by investment from Microsoft, which is seen as a leader in AI adoption and has begun many AI upgrades.

SoftBank will hold its annual general meeting on Wednesday with the market looking for details of Son's investment outlook at a time when interest in AI is driving capital expenditure around the world.

Son has long argued that AI is the driving force behind his investing activity. However, he has had to contend with high-profile stumbles such as office-sharing firm WeWork and weakness in valuations of the high-growth startups he favors.

A successful listing of Cambridge, England-based Arm would be seen as providing a much-needed win for the indebted Japanese conglomerate, whose long-term credit rating was last month cut by S&P Global Ratings, citing its exposure to unlisted companies.

As observers debate Son's ability to pick winners in an economy expected to be increasingly powered by AI, his group's shares have been swept up in a frenzy for chip and AI-related stocks, gaining around 30% quarter-to-date.