SoftBank SB Energy seeks $500 million from Japan ahead of a US listing

SB Energy, the SoftBank-backed developer that pairs data centres with power plants, said in a Japanese filing on 15 September that it will offer up to $500 million of new shares to investors in Japan as part of a planned listing in the United States. Orders could open this month. The filing named Mizuho, Daiwa, PayPay Securities, Rakuten Securities and SBI Holdings as selling agents for Mizuho US arm. Proceeds are earmarked for data centres, generation and related infrastructure.

The company has already filed for a US IPO this month. It has not published the size of the American book. Reuters has reported that SoftBank may seek a valuation near $50 billion. Nvidia has committed $1.5 billion in a private placement at the IPO price. OpenAI holds warrants SB Energy has put at about $5.5 billion. The US prospectus, released earlier in September, said the firm has 8.8 gigawatts of data-centre capacity contracted or under construction at campuses in Texas and Ohio, tied to solar and battery storage.

The Japan tranche is a demand test and a fundraising channel at the same time. Household financial assets in Japan are about $15 trillion. SpaceX sold $2.2 billion of stock to Japanese buyers in its June listing. SB Energy is trying to tap the same pool before US bookrunners set a price. Pre-sold Japanese paper can make the deal look partly spoken for. It can also leave the US offer looking smaller than the headline valuation if Tokyo takes a large slice of new shares.

UBS has put power spending needed by 2030, much of it for data centres, at $511 billion. That is the story SB Energy is selling: not a software multiple, a campus plus a power plant. SoftBank already links the firm to OpenAI and to Nvidia. The risk is the same risk hanging over every AI infrastructure listing this year. If training demand slows, or if grid connections slip, 8.8 gigawatts of contracted capacity becomes a delay notice rather than a revenue line.

The filing is careful about use of proceeds. It talks about operating costs for development, not about retiring SoftBank debt. That will be read against whatever capital structure the US prospectus shows. Investors in Tokyo who buy the $500 million slice will be buying a US-listed name whose main assets sit in Texas and Ohio and whose largest strategic holders are an American chipmaker and an American lab.

The next number that matters is the US offer size. Until that figure is public, $50 billion is a reported target and $500 million is the only hard subscription line on the page. Bookbuilding in Japan will show whether domestic buyers still want AI power names after SpaceX, or whether this is the deal that prices the fatigue.