TOKYO - SoftBank Group announced on September 24 that it will issue approximately 1.76 trillion yen worth of foreign currency-denominated bonds, the largest simultaneous bond offering in its history, to finance a further $10 billion investment in OpenAI as founder Masayoshi Son accelerates his strategy of building a global business spanning artificial intelligence, semiconductors and data centers.
The offering, aimed at overseas institutional investors, consists of $10 billion in U.S. dollar-denominated bonds and 1 billion euros in euro-denominated bonds. The proceeds will primarily fund the third and final installment of a $30 billion additional investment in OpenAI announced in February 2026, with payment scheduled for October 1.
The financing marks another major step in SoftBank's transformation from a telecommunications and internet investment company into one of the world's largest investors in AI. Son has spent the past decade assembling a portfolio of businesses covering the technology needed to develop, operate and commercialize increasingly sophisticated AI systems.
An early milestone came in 2016, when SoftBank acquired British semiconductor designer Arm for approximately 3.3 trillion yen. Although Arm was then best known for designing processors used in smartphones, Son viewed its energy-efficient chip technology as a foundation for the next generation of computing, including artificial intelligence, connected devices and cloud infrastructure.
SoftBank expanded its technology investments in 2017 with the launch of its first Vision Fund, which secured more than $93 billion in initial commitments. The fund invested heavily in technology companies across industries including transportation, robotics, artificial intelligence and financial services, giving SoftBank exposure to businesses seeking to transform established markets through digital technology.
The company subsequently established Vision Fund 2, increasing its focus on emerging technologies and AI-related businesses. Its portfolio has included companies developing enterprise software, machine learning applications and the infrastructure needed to support increasingly powerful AI systems.
SoftBank began investing directly in OpenAI in September 2024, marking a major shift toward generative AI. Its investments subsequently expanded as the company behind ChatGPT sought additional capital to develop more advanced models and build the computing infrastructure required to operate them.
The investment strategy accelerated in 2025, when SoftBank committed to a funding arrangement of up to $40 billion for OpenAI, with part of the investment allocated to outside investors. By the end of December 2025, SoftBank had completed $30 billion in investments under the arrangement, bringing its ownership of OpenAI to approximately 11%.
SoftBank's AI ambitions have extended beyond OpenAI. In July 2024, it acquired British AI chip developer Graphcore, strengthening its semiconductor capabilities alongside Arm. It also announced a $6.5 billion acquisition of U.S. chip designer Ampere Computing in March 2025, bringing additional expertise in processors designed for cloud computing and AI workloads.
The company has sought to bring these semiconductor businesses together as part of a broader AI computing strategy, positioning Arm, Graphcore and Ampere to supply technologies for the rapidly expanding market for AI processing.
Another major initiative emerged in January 2025, when SoftBank joined OpenAI, Oracle and investment firm MGX in announcing the Stargate Project, an ambitious plan to invest up to $500 billion over four years in AI infrastructure in the United States. Under the arrangement, SoftBank assumed financial responsibility while OpenAI took responsibility for operations, with Son serving as chairman.
The partnership also extended to Japan, where SoftBank and OpenAI announced plans in February 2025 to develop Cristal intelligence, an enterprise AI platform intended to help companies integrate advanced AI into their operations.
SoftBank deepened its commitment to OpenAI in February 2026, announcing a further $30 billion investment divided into three installments of $10 billion each. The first two payments were made in April and July, with the final installment scheduled for October 1. Completion of the investment is expected to bring SoftBank's cumulative investment in OpenAI to approximately $64.6 billion, representing an ownership stake of around 13%.
To finance the expansion, SoftBank arranged a $40 billion bridge loan facility in March 2026. The latest bond issuance will provide funding for the remaining OpenAI payment while allowing the company to cancel $10 billion in unused borrowing capacity under the facility.
The scale of the financing highlights the growing importance of OpenAI to SoftBank's investment portfolio, alongside its semiconductor holdings and expanding AI infrastructure businesses. It also increases the company's financial exposure to the commercial success of AI technology as Son continues to commit substantial resources to the sector.
Source: テレ東BIZ
