Mitsui & Co.

Warren Buffett began accumulating shares in Mitsui & Co. and four other Japanese trading houses in August 2020, citing their diversified commodity portfolios, discounted valuations, and shareholder-friendly capital return policies. Berkshire's stake in Mitsui rose to roughly 8% by 2023, making it one of the firm's largest outside shareholders. Buffett has publicly praised the sogo shosha model for its global diversification and cash-flow generation.

Mitsui typically identifies long-term structural demand trends — such as urbanization in Asia or the energy transition — and originates direct stakes in operating assets, joint ventures, or project-finance structures. The firm maintains industry-specific investment teams housed within its business units, rather than operating a centralized private equity fund, and can hold assets indefinitely. Mitsui rarely leads competitive auctions, preferring to co-develop projects with industrial partners like Toyota, Penske, or regional commodity producers.

Mitsui & Co. was the trading arm of the pre-war Mitsui zaibatsu, one of Japan's four largest family-controlled industrial conglomerates. The zaibatsu was dissolved under Allied occupation in 1947, and Mitsui & Co. re-formed as an independent general trading company shortly thereafter. Though the formal holding-company structure no longer exists, Mitsui & Co. maintains cross-shareholding and business relationships with Sumitomo Mitsui Financial Group and other descendant entities.

Mitsui predominantly pursues direct investments through equity stakes in operating companies and project-level joint ventures. The firm also participates in fund commitments selectively, particularly through real estate vehicles such as the Japan Logistics Fund and the MBRM Fund managed by Mitsui & Co. Realty Management. Its corporate venture capital arm targets early-stage companies, particularly in digital transformation and Web3.

Mitsui has not published a formal exclusion list, but its portfolio reflects a de facto avoidance of pure-play consumer internet and short-cycle retail. The firm typically skirts sectors where its long-hold advantage is diluted by rapid technological obsolescence or where it cannot leverage its existing industrial relationships and infrastructure. Defense contracting is also notably absent from its publicly disclosed activities.

Mitsui will co-invest alongside financial sponsors — including its own majority-owned fund managers — in real estate, aviation, and infrastructure deals where the firm brings operating expertise or commodity offtake rights. External GPs report that Mitsui typically negotiates for board representation and governance rights commensurate with its equity position.

Mitsui operates the Mitsui & Co. Co-creation Fund in Japan and the Mitsui U.S.A. Foundation in the United States, both of which focus on education, environmental conservation, and community development. These entities are funded through corporate contributions rather than a separate philanthropic trust tied to founding-family wealth. The firm also maintains the Mitsui Memorial Museum in Tokyo, which houses a significant collection of Japanese art and artifacts.