6 min read
Masayoshi Son's net worth was $64 billion, per Forbes, as of 19 July 2026, ranking him 30th globally. Ten weeks earlier, the same publisher had him at $80 billion: Forbes' "Japan's 50 Richest 2026" list, priced as of 22 May 2026, showed his fortune up $51.8 billion, or 184%, from a year earlier, the single largest gain on the list in both dollar and percentage terms, and enough to make him Japan's richest person again for the first time since 2021. Both figures are Forbes, so the $16 billion gap between them is one publisher's own number moving, not two trackers disagreeing.
Forbes priced Masayoshi Son at $80 billion on its "Japan's 50 Richest 2026" list, valuations dated to the close of markets on 22 May 2026 and the list published 8 June 2026, crediting SoftBank Group's record ¥5 trillion (about $31 billion) net profit for the fiscal year ended 31 March 2026, driven largely by gains tied to its OpenAI stake. Within two weeks, Forbes reported his fortune had fallen by about $13 billion as SoftBank shares slid, costing him the "Asia's richest" title he had briefly held (4 June 2026), and a further Forbes report on 11 June 2026 described an additional slump of nearly $22 billion in the following week amid a continued SoftBank selloff. By 19 July 2026, Forbes' real-time figure had settled at $64 billion. This run's searches found no Forbes or other named-tracker figure dated later than 19 July 2026, so that is the most current sourced number available, already more than two months old given how fast this fortune has moved this year.
| Date | Publisher | Figure | Context |
|---|---|---|---|
| 22 May 2026 (list pricing date) | Forbes, "Japan's 50 Richest 2026" | $80 billion | Up 184% year on year, Japan's #1 again |
| 4 June 2026 | Forbes | down ~$13 billion | Lost "Asia's richest" title as SoftBank shares slid |
| 19 July 2026 | Forbes (real-time) | $64 billion | 30th globally |
SoftBank's own disclosures, as reported by The Motley Fool (19 August 2026), put Son's direct stake at about 29.88% of SoftBank Group as of 31 March 2026, with a further stake held through Son Asset Management, LLC, a holding vehicle he controls. Nearly all of his tracked wealth runs through that one company rather than a diversified portfolio. SoftBank's two largest identifiable assets are its majority stake in chip designer Arm Holdings (ARM) and its rapidly growing position in OpenAI, built through the Vision Fund. Per SoftBank Group's own investor announcement (27 February 2026) and subsequent reporting, the company had committed to invest $30 billion more into OpenAI as part of a $122 billion round completed in March 2026, bringing its cumulative OpenAI investment to $64.6 billion for roughly a 13% stake. Neither ARM nor SoftBank Group itself (Tokyo-listed as 9984, OTC as SFTBY) is present in NetWort's curated ticker universe (frontend/scripts/curated-tickers.mjs, backend/app/services/asset_symbol_service.py), checked this run, so both are named here without a link.
The OpenAI bet is now a financing story as much as an investment one. SoftBank launched what multiple outlets described as the largest junk-bond offering ever from Asia-Pacific, seeking over $11 billion (Bloomberg, 21 September 2026) to fund the final tranche of its $30 billion OpenAI commitment, meaning a meaningful slice of the position behind Son's tracked fortune is now debt-financed rather than paid from cash on hand. Separately, this year's swings have put Son at the center of a title that has changed hands repeatedly in 2026: this series has now covered three people, Son, Mukesh Ambani, and Gautam Adani, who each briefly held Forbes' "richest person in Asia" title within the same year, a reshuffle driven as much by AI-linked stock moves as by any single company's underlying earnings.
This is one of the more volatile tracked fortunes this series has covered. A $30 billion-plus swing inside a single quarter, and a $16 billion gap between two Forbes figures just ten weeks apart, both come from the same publisher pricing the same SoftBank shares differently as they moved, not from a methodology dispute. That volatility is structural: Son's wealth is concentrated in one holding company whose own balance sheet is now leveraged against a single, unlisted AI bet. A number this sensitive to a stock's daily close is, almost by definition, out of date within days of being published, more so than for a fortune anchored in a stable, diversified portfolio.
When most of a tracked fortune sits in one company, and that company is itself making a leveraged bet on a single unlisted asset, the tracked number can move tens of billions of dollars in weeks without any change in the underlying business the company actually sells. For related mechanisms elsewhere in this series, see:
NetWort's market page tracks how publicly traded companies are moving today, the same kind of daily pricing that drives a fortune as concentrated as Son's.