Visiting the De Beers HQ in Charterhouse Street in London some two decades ago, it was difficult not to be swept along by the obvious power and control of the global diamond trade that the mining giant enjoyed at the time. Even the fact that the decor, in the giant offices, was so clearly from another era lent a further strengthening to the grip of power the firm exercised.
The pictures of the famous members of the Oppenheimer family through the decades on the walls further added to the luster. Just looking at those pictures took visitors back to the glory days of the discovery and exploitation of diamond reserves on the African continent, while the enormous offices in the heart of London left nobody in any doubt that De Beers was the undoubted king of diamonds.
Even at that time, however, the company’s decline in control of the rough diamond trade was becoming evident. Some years later, De Beers and Botswana came to a diamond mining agreement in which sightholders would have to fly to Gaborone to inspect their diamond parcels. De Beers, of course, put a brave face on the move.
In private discussions with officials, I (and many others) questioned whether De Deers could survive the move. Would sightholders really be prepared to take flights of 10 hours or so from Europe to Botswana? As sightholders explained, flying into London to view sights enabled them to hold other meetings, as well as ample recreational opportunities.
Was the country entirely safe? Was even electricity and Internet stable. Was the water supply safe? What was there to do in Gaborone?
How The Mighty Are Fallen
For more than a century, De Beers had been the undisputed king of the global diamond industry. At its peak, the company controlled the overwhelming majority of the world's rough diamond supply and effectively dictated prices, distribution, and marketing.
Today, however, the industry looks very different. The latest evidence of that transformation came in March when De Beers cut its number of authorized sightholders by roughly one-third.
The move is significant not only because it affects dozens of diamond manufacturers and traders worldwide, but because it highlights how far De Beers has declined from its days as one of the most powerful monopolies in modern business history.
From Near-Total Control to Industry Giant
Founded in 1888 by Cecil Rhodes, De Beers spent much of the 20th century building an extraordinary degree of control over the diamond trade.
For decades, the company operated through a system known as the Central Selling Organisation (CSO), which purchased diamonds from producers around the world and released them into the market in carefully controlled quantities. By regulating supply, De Beers maintained price stability and ensured diamonds remained scarce and valuable.
During much of the 20th century, De Beers controlled more than 80% of global rough diamond supply. Some estimates place its market share at around 90% during the 1980s. Even in the late 1990s, the company still controlled over 80% of the market.
Its influence extended beyond mining. Through the legendary "A Diamond Is Forever" advertising campaign created after the Second World War, De Beers helped create the modern diamond engagement ring tradition and shaped consumer demand across the world. The company became so dominant that many observers referred to it as the diamond cartel.
The Rise of the Sightholder System
One of De Beers' most important tools was its sightholder system. Selected companies were invited to attend regular "sights" where they could purchase boxes of rough diamonds directly from De Beers. These invitations were highly coveted because they provided access to a consistent supply of rough stones.
Many companies made a handsome profit by simply selling the rough goods on to the secondary market rather than cutting and polishing goods for which they might not ultimately have customers.
Even today, Global Sightholder Sales account for approximately 90% of De Beers' rough diamond sales by value. The system remains the company's primary route to market.
For decades, being a De Beers sightholder represented prestige, security, and access to one of the most important sources of rough diamonds in the world.
The Monopoly Starts to Crumble
The decline of De Beers' dominance began in the 1990s. New diamond producers, including miners in Russia, Canada, and Australia, increasingly chose to sell their production independently rather than through De Beers' distribution channels.
At the same time, antitrust concerns – especially in the European Union and the United States – and changing market dynamics made it more difficult for the company to maintain its traditional control over supply.
By 2000, De Beers' share of global diamond supply had fallen to approximately 63%. The company responded by abandoning its role as market controller and shifting toward a more conventional luxury-brand strategy.
Today, De Beers is still one of the world's largest diamond producers, but it no longer possesses the market power that once allowed it to determine industry-wide pricing. Industry analysts estimate its share of rough diamond production is now roughly one-third of global supply by value, far below historic levels.
Why De Beers Is Reducing Sightholder Numbers
The latest reduction in sightholders did not come as a complete surprise to industry observers.
Industry reports in late 2024 indicated that De Beers planned to reduce the number of companies receiving direct supply contracts when the next contract period began in 2026.
At the time, the company had approximately 60 sightholders and was already signaling a desire to work with a smaller, more focused group of clients.
In March 2026, reports showed that more than 20 companies had lost their status, reducing the total number of sightholders from about 69 to roughly 45. This was widely seen as one of the largest revisions to the sightholder list in years.
Let’s take a look at the factors that drove the decision:
1. Weak Demand for Natural Diamonds
The natural diamond industry has faced one of its most challenging periods in decades. Demand weakened significantly following the post-pandemic boom, particularly in China, historically one of the industry's most important markets.
2. Competition from Lab-Grown Diamonds
Perhaps the biggest structural challenge has been the rapid growth of lab-grown diamonds.
These stones have become dramatically cheaper and increasingly accepted by consumers, especially in the bridal jewelry market. Industry reports point to lab-grown diamonds as a major reason for reduced demand for natural stones and falling prices throughout the supply chain.
3. Industry Consolidation
Diamond manufacturing has become increasingly concentrated among larger, financially stronger companies. Smaller manufacturers have struggled with tighter margins, higher financing costs, and weaker demand. De Beers appears to be responding by focusing its supply on larger clients that can support long-term strategic partnerships.
4. Reduced Rough Availability
De Beers and its government partners in Botswana, Namibia, South Africa, and Canada have sought to align supply contracts with available production and long-term market realities. A smaller customer base allows the company to allocate larger volumes to its preferred clients.
What De Beers Says
While De Beers has not publicly confirmed the exact number of sightholders removed, the company has consistently framed the changes as part of a broader strategy to build deeper relationships with a more focused group of customers.
Industry reports quote De Beers as seeking to work with a "more focused group of clients" and align its distribution model with its evolving "Origins" strategy, which emphasizes traceability, branding, and differentiation of natural diamonds from laboratory-grown alternatives.
The company also continues to argue that natural diamonds possess unique emotional, geological, and luxury characteristics that cannot be replicated by manufactured stones. Through new marketing initiatives and industry reports, De Beers is attempting to reinforce consumer demand for natural diamonds despite challenging market conditions.
What the Future Holds
The reduction in sightholders is more than an administrative change. It reflects a broader transformation of the diamond industry.
The era when De Beers could single-handedly control global supply has long passed. The company now faces competition not only from rival miners but also from lab-grown diamonds, shifting consumer preferences, geopolitical uncertainty, and changing distribution models.
Yet De Beers remains one of the most influential names in the business. While it no longer commands the 80% to 90% market share it enjoyed during its largely monopoly years, it continues to sell approximately 90% of its own production through the sightholder system and remains a central force in the natural diamond market.
The latest cut in sightholders suggests that De Beers believes the future lies not in serving the largest possible network of buyers, but in building stronger relationships with a smaller group of financially robust partners. Whether that strategy can help revive the natural diamond sector amid the rise of lab-grown stones will be one of the defining questions facing the industry over the next decade.
Philip Carter for Rough&Polished from London
