Marubeni

Warren Buffett began accumulating Marubeni — alongside the four other major Japanese trading houses — in August 2023 and subsequently raised the stake to 9.8% in 2024. In shareholder communications, he cited their diversified, asset-heavy portfolios, disciplined capital-return policies, and valuations that resembled Berkshire's own early-stage acquisition multiples more than those of a typical conglomerate. The position gives Berkshire passive exposure to global commodity flows and infrastructure cash flows.

Marubeni takes direct equity stakes in the mines, carriers, pipelines and processing plants that move physical goods, rather than only earning a margin on third-party cargoes. It co-owns the Roy Hill iron ore mine in Australia, holds an interest in the Los Pelambres copper mine in Chile alongside Antofagasta plc, and controls Aircastle, a large-scale aircraft lessor, through a joint venture with Mizuho. These positions generate recurring production-linked earnings that an agency-only trader does not capture.

Copper, iron ore, and liquefied natural gas anchor the resource portfolio. The Los Pelambres mine produces copper concentrates that feed Asian smelters, while Roy Hill ships iron ore to steel mills in Japan, China, and Korea. Marubeni also operates a fleet of LNG carriers that service long-term off-take agreements. Alongside metals and energy, the firm moves significant volumes of grain and forest products.

Its non-resource businesses include a residential-property development operation spanning China and India, an aircraft-leasing platform co-owned with Mizuho, and a venture arm exploring advanced air mobility and quantum-inspired AI compression. The firm also maintains the TradeWaltz digital-trade platform in Japan and holds strategic membership in the Japan Business Aviation Association via its aerospace unit.

The Marubeni Foundation functions as a legally distinct grant-making entity that funds social-welfare programs, disaster relief, and cultural preservation — including the Marubeni Gallery, which holds a textile collection and the La Bella Simonetta artwork. The foundation's budget is allocated from a portion of corporate profits, keeping philanthropic governance separate from the trading and investment balance sheet.

Marubeni operates across a wide swath of the real economy but does not emphasize consumer-facing technology, biotech, or software-as-a-service businesses. Its venture activity — such as the April 2026 memorandum with Multiverse Computing — focuses on industrial applications rather than pure-play digital platforms. The firm's public statements concentrate on physical commodities, infrastructure, and adjacent industrial technology.

Marubeni operates through division-level investment committees under a president and CEO who reports to the board of directors. Sector heads within the Food, Forest Products, Energy, Chemicals, and Power divisions originate deals, while the corporate planning function allocates capital across the group. The presence of Berkshire Hathaway as the largest major shareholder adds an external discipline to capital-allocation decisions.