Anglo American plc (LSE: AAL) is a London-headquartered multinational mining group and the majority shareholder — holding approximately 85 per cent — of De Beers Group, the most consequential organisation in the history of the diamond trade. De Beers was founded in 1888 by Cecil Rhodes in the Kimberley mining fields of South Africa, and for much of the twentieth century it operated what was, in practical terms, a global supply cartel: at its peak, the company controlled an estimated 80–90 per cent of the world's rough diamond production and distribution. Although its market share has contracted substantially since the 1990s, De Beers remains the single largest producer of rough diamonds by value and a defining force in diamond mining, marketing, and — increasingly — laboratory-grown diamond production.

Corporate Structure and Ownership

The relationship between Anglo American and De Beers is long-standing and deeply interwoven. Anglo American was itself founded in 1917 by Ernest Oppenheimer, who subsequently acquired control of De Beers in 1929, consolidating the two entities under Oppenheimer family influence for most of the twentieth century. The Oppenheimer family sold their remaining 40 per cent stake in De Beers to Anglo American in 2011 for approximately US$5.1 billion, ending nearly a century of family stewardship. The Government of the Republic of Botswana holds the remaining 15 per cent of De Beers, a stake that reflects the critical importance of Botswana's Jwaneng and Orapa mines to De Beers's production base.

Anglo American itself is publicly listed on the London Stock Exchange and is a diversified miner with interests in platinum group metals, copper, iron ore, and coal, in addition to diamonds. De Beers therefore represents one segment — albeit a strategically and symbolically significant one — within a broader portfolio. In 2024, Anglo American announced a strategic review of its asset portfolio under pressure from a takeover approach by BHP Group, raising questions about the future ownership structure of De Beers; as of the time of writing, a partial or full divestiture of the De Beers stake remained under active consideration.

The Sights System and the Central Selling Organisation

To understand De Beers's historical dominance, one must understand the sights system — arguably the most unusual distribution mechanism in any major commodity market. For most of the twentieth century, De Beers channelled the overwhelming majority of global rough diamond supply through a single entity known at various times as the Diamond Trading Company (DTC) or, earlier, the Central Selling Organisation (CSO), based in London. Approved buyers — known as sightholders — were invited to attend approximately ten sales per year, called sights, at which they received pre-assembled parcels of rough diamonds at prices set unilaterally by De Beers. Sightholders were not permitted to negotiate the contents or the price of their parcel; they could accept it in full or decline it entirely, though repeated refusals risked loss of sightholder status.

The system gave De Beers extraordinary leverage: by controlling both supply and the terms of sale, it could smooth price volatility, stockpile rough during downturns, and release supply strategically during periods of strong demand. The sightholder list was itself a coveted commercial asset — access to consistent, quality rough supply at predictable intervals was the foundation upon which major cutting and polishing operations in Antwerp, Tel Aviv, Mumbai, and New York were built.

In 2000, De Beers overhauled the sights system under its "Supplier of Choice" programme, introducing formal criteria — financial strength, downstream marketing capability, adherence to the Kimberley Process — that sightholders were required to meet. The number of sightholders was reduced substantially, and the programme shifted emphasis from mere volume purchasing to value-added downstream activity. The Diamond Trading Company relocated its primary sight operations to Gaborone, Botswana, in 2013, a move that reflected both the political importance of Botswana and the terms of the company's mining agreements with the Botswana government through the joint venture Debswana.

Mining Operations and Key Localities

De Beers's production is geographically concentrated in four countries:

• Botswana — through the Debswana joint venture (50/50 with the Botswana government), De Beers operates Jwaneng, the world's richest diamond mine by value, and the Orapa and Damtshaa mines. Botswana accounts for the majority of De Beers's carat production.
• South Africa — the historical heartland of De Beers, including the Venetia mine in Limpopo province, which transitioned to underground operations in the 2020s to extend its life. The original Kimberley mines, though no longer productive, remain a heritage site of global significance.
• Namibia — through Namdeb (a 50/50 joint venture with the Namibian government), De Beers operates both onshore alluvial mining and, through De Beers Marine Namibia, extensive seabed mining along the Orange River coast. Namibian production is notable for its high proportion of gem-quality stones.
• Canada — the Gahcho Kué mine in the Northwest Territories (a joint venture with Mountain Province Diamonds) and the now-closed Snap Lake mine represented De Beers's entry into Canadian production following the discovery of kimberlite pipes in the 1990s.

Decline of the Monopoly and the Kimberley Process

De Beers's grip on global supply began to loosen in the 1990s for several reasons. The emergence of significant producers outside De Beers's influence — most notably the Argyle mine in Western Australia (Rio Tinto), Russian production through ALROSA, and later Canadian mines — eroded the CSO's ability to control global supply. Russia's ALROSA, which accounts for a substantial share of global rough production, has operated independently of De Beers throughout its post-Soviet history.

Simultaneously, the issue of conflict diamonds — rough stones used to finance armed insurgencies in Angola, Sierra Leone, and the Democratic Republic of Congo — generated intense international scrutiny of the diamond trade in the late 1990s and early 2000s. The response was the Kimberley Process Certification Scheme (KPCS), established in 2003, which requires participating governments to certify that rough diamond exports are conflict-free. De Beers was a prominent supporter of the Kimberley Process, recognising that consumer confidence in diamonds was essential to the value of its own product.

By the early 2000s, De Beers's share of global rough diamond supply had fallen to roughly 40–45 per cent by value, a figure that has continued to decline gradually. The company also settled long-running antitrust litigation in the United States in 2004, paying US$295 million and acknowledging, for legal purposes, certain past conduct — a settlement that finally allowed De Beers to operate openly in the American market after decades of legal exposure.

Forevermark and Laboratory-Grown Diamonds

De Beers has pursued downstream brand-building through Forevermark, a diamond brand launched in 2008 that inscribes a proprietary mark — invisible to the naked eye — on the girdle of qualifying natural diamonds, certifying their provenance and quality standards. Forevermark operates primarily in Asian markets, particularly China, India, and Japan.

In 2018, De Beers made a strategically significant and widely noted move by launching Lightbox Jewelry, a direct-to-consumer brand selling laboratory-grown diamonds at deliberately low, fixed price points (initially US$800 per carat). The move was interpreted by many industry observers as a deliberate effort to commoditise the laboratory-grown segment and thereby protect the perceived value of natural diamonds — a strategy consistent with De Beers's long history of supply and price management, applied now to a synthetic competitor rather than a rival miner.

Significance for Investors and the Trade

For investors, Anglo American offers listed equity exposure to diamond mining alongside a diversified base metals portfolio. De Beers's diamond revenues are sensitive to consumer sentiment in key markets — the United States, China, India, and the Gulf — as well as to the US dollar, in which diamonds are globally priced. The structural challenge posed by laboratory-grown diamonds to natural diamond pricing has become a central concern for analysts covering Anglo American, particularly as price premiums for natural stones have faced pressure in the sub-two-carat commercial range.

For the trade, De Beers's sightholder allocations remain a barometer of market health: parcel sizes, pricing adjustments, and the composition of sight boxes are closely watched indicators of De Beers's assessment of downstream demand. The company's willingness to adjust prices or defer sights — as occurred during the 2008–09 financial crisis — demonstrates that the supply-management philosophy of the CSO era has not entirely disappeared, even if the monopoly that underpinned it has.

Further Reading

• GIA Gems & Gemology — Diamond Industry Overview
• De Beers Group — Our Business (official)
• Kimberley Process Certification Scheme — official site