SoftBank Group's stock reached a record high on Monday, pushing its market capitalization beyond ¥40 trillion ($252 billion). The stock has surged 40% since May 20, driven by investor optimism over potential IPOs of its stakes in OpenAI and SB Energy. OpenAI is reportedly preparing for an IPO, while SB Energy plans a confidential filing in the U.S. Analysts suggest these moves could significantly boost SoftBank's returns and enhance valuation transparency in the AI sector.