ECON 499 - Practice Exam 4: De Beers and U.S. Antitrust Law

Applying the SSNIP test to each candidate market:

Candidate (i): "All luxury goods"

If a hypothetical monopolist of all luxury goods raised prices by 5%, would enough consumers substitute away - to non-luxury goods - to make the increase unprofitable? Almost certainly not. Luxury consumers have already self-selected into this category; they are price-insensitive relative to the general population. A 5% price increase on all luxury goods simultaneously is profitable. But this market is clearly over-inclusive: a diamond monopolist cannot control watches, handbags, or yachts. Including them obscures De Beers's power rather than measuring it.

Candidate (ii): "All jewelry"

If a hypothetical monopolist of all jewelry raised prices by 5%, would consumers switch away to, say, clothing or electronics? For many consumers, jewelry - particularly diamonds - is purchased for specific emotional and social occasions (engagement rings, anniversaries) where non-jewelry goods are not substitutes. Demand is inelastic enough that this market is still too broad; it dilutes De Beers's measured power by including silver, gold, and costume jewelry that De Beers does not control.

Candidate (iii): "Rough gem diamonds"

If a hypothetical monopolist of rough gem diamonds raised prices by 5%, would enough consumers shift to other gemstones (rubies, sapphires, emeralds) to make the increase unprofitable? The answer is likely no. Diamonds occupy a unique cultural position - specifically in engagement rings - that is not easily substitutable by other gems. De Beers's own advertising ("A Diamond is Forever") deliberately reinforced this uniqueness. Demand-side substitution away from diamonds for the specific occasion-purchase use case is limited. The increase is profitable.

Conclusion: The relevant market is rough gem diamonds. This is the narrowest definition that still constitutes a self-contained market, and it is where De Beers's power is concentrated.

Effect on market power assessment: The narrow definition reveals De Beers's 80% market share - clearly consistent with monopoly power. A broad "all jewelry" definition would dilute this to a much smaller share, potentially obscuring the monopoly entirely. As always, the narrower the market definition, the higher the measured concentration - and De Beers's power was only visible with the correct narrow definition.

Setting up the calculation:

The competitive price represents the marginal cost in a competitive market:

MC = $1,000/carat (competitive price = MC in perfect competition)

De Beers's price: P = $1,500/carat

Lerner Index:

L = (P − MC) / P = (1,500 − 1,000) / 1,500 = 500 / 1,500 = 1/3 ≈ 0.33

Interpretation: De Beers prices approximately 33% above marginal cost. While lower than the pharmaceutical example in earlier practice exams, this still represents substantial market power. In a competitive market L = 0; here L = 0.33 indicates a firm with meaningful pricing power above cost.

Implied price elasticity:

For a profit-maximizing monopolist: L = 1/|εd|

|εd| = 1 / (1/3) = 3.0

Demand is moderately elastic: a 1% price increase causes approximately a 3% reduction in quantity. This may seem surprisingly elastic for a luxury good, but it reflects that at the margin - the 150M carats sold competitively vs. 100M under monopoly - some buyers are substituting away as prices rise significantly. Diamonds are not perfectly inelastic; at some price, gifting and jewelry consumption does decline.

Consistency check: An L of 0.33 in the narrow "rough gem diamonds" market is internally consistent. It reflects a firm that has substantial but not total pricing power - consistent with an 80% market share in a market where some substitution does occur at elevated prices. If we had used the broader "all jewelry" market, De Beers's implied market share would be much smaller, and an L of 0.33 would appear anomalously high relative to that share - signaling the broad definition was incorrect.

Given values:

• Competitive: P_c = $1,000/carat, Q_c = 150M carats
• Monopoly: P_m = $1,500/carat, Q_m = 100M carats
• ΔP = $500/carat | ΔQ = 50M carats

Deadweight loss (DWL):

DWL = ½ × ΔP × ΔQ = ½ × $500 × 50,000,000 = **$12,500,000,000**

The deadweight loss is $12.5 billion per year - welfare that is permanently destroyed because 50 million carats that buyers would have purchased at the competitive price are no longer produced.

Transfer rectangle:

Transfer = ΔP × Q_m = $500 × 100,000,000 = **$50,000,000,000**

$50 billion per year is transferred from diamond buyers (consumers, jewelry manufacturers, retailers) to De Beers. This is a redistributional loss - not a social welfare destruction - but it is central to the political and legal controversy surrounding De Beers.

Diagram description (draw this on the exam):

• Horizontal axis: Quantity (carats/year). Mark Q_m = 100M and Q_c = 150M.
• Vertical axis: Price ($/carat). Mark P_c =$1,000 and P_m = $1,500.
• Downward-sloping demand curve and horizontal MC = $1,000 line (assuming constant MC for simplicity).
• Competitive equilibrium at (150M, $1,000). Monopoly at (100M,$1,500).
• Large rectangle from P_c to P_m, spanning 0 to Q_m: $50B transfer from consumers to De Beers.
• Triangle with vertices at (100M, $1,500), (100M,$1,000), and (150M, $1,000): **$12.5B DWL** - pure welfare destruction.

Key insight: The transfer ($50B) massively exceeds the DWL ($12.5B). This is typical of monopolies - most of the consumer harm is redistribution to the monopolist, not efficiency loss. However, from a consumer welfare standpoint, both the transfer and the DWL are harmful to buyers.

Evaluating the argument on its merits:

De Beers's claim has a kernel of economic truth. In unmanaged commodity markets, volatile prices can impose costs on producers and consumers alike - investment uncertainty, feast-or-famine cycles, information problems about quality. If consumers genuinely value price predictability and quality consistency, some welfare gain may offset part of the DWL.

However, even accepting this argument at face value, the numbers undermine it:

• De Beers's monopoly pricing transfers $50 billion annually from buyers to De Beers.
• The "stability" benefit accrues primarily to De Beers (stable, high revenues) not to consumers (who pay 50% above competitive prices permanently).
• A competitive market with some regulatory quality standards could achieve quality assurance without the $12.5B annual welfare destruction and$50B transfer.

The price stability argument also conveniently ignores that De Beers created its own pricing power - the "stability" is achieved by restricting supply, which is precisely the anticompetitive conduct at issue.

Is it a valid defense under US law?

No. The CSO's output restriction is per se illegal price-fixing under Sherman Act §1. Under the per se rule, no efficiency or pro-consumer justification - including price stability - can be weighed against the anticompetitive conduct. The argument would only be relevant under the rule of reason, which does not apply to naked output coordination among horizontal competitors.

The argument resembles the "Chicago School paradox" discussed in the case: De Beers claims the monopoly benefits consumers by maintaining diamond value and market confidence. But even if true, US antitrust law - particularly for per se violations - does not permit this trade-off. The per se rule exists precisely because courts have found that the harm from price-fixing is so consistent and the pro-competitive justifications so rarely valid that case-by-case balancing is not worth the effort.

Relevant provision: Sherman Act Section 1

Section 1 prohibits "every contract, combination... or conspiracy in restraint of trade." The CSO is a textbook example: independent diamond producers (who would otherwise compete against each other in selling rough diamonds) have entered an agreement - the CSO participation contract - under which they collectively hand output to De Beers for coordinated sale. This is a horizontal agreement among competitors to restrict output and fix selling prices.

Standard of review: Per se illegal

Output restriction and price-fixing among horizontal competitors are per se illegal. No weighing of pro-competitive benefits is permitted. The fact that producers "voluntarily" join the CSO does not save the arrangement - coercion and voluntary participation are both sufficient for §1 liability once a conspiracy to restrain trade is established.

Mapping the conduct to the elements:

1. Agreement: The CSO participation contracts are explicit written agreements. Every producer who hands diamonds to De Beers has formally agreed to the arrangement.
2. Among competitors: The producers - South African, Russian, Botswana, Namibian mining companies - all produce the same product (rough diamonds) and would compete against each other in its absence.
3. Restraint of trade: The agreement restrains output (producers cannot sell independently), fixes prices (De Beers sets non-negotiable sight prices), and allocates the market (only CSO sightholders can purchase).

All three elements are satisfied. The CSO violates Sherman Act §1 per se.

Why cartels are unstable:

Each cartel member has a private incentive to defect: by selling more than its quota at the elevated cartel price, it captures extra revenue. But if all members defect, supply rises and prices collapse. This prisoner's dilemma means cartels tend to break down as cheating accumulates - especially over long time horizons.

Four features that made the De Beers cartel exceptionally durable:

1. De Beers as the sole buyer and seller (monopsony-monopoly combination). Unlike a typical cartel where multiple firms must trust each other, De Beers created a structure where it was the single centralized buyer of all rough diamonds. Producers did not coordinate prices among themselves - they handed production to De Beers. This eliminated the monitoring problem entirely: there was no need to detect cheating among members because De Beers controlled all flows. The architecture made defection nearly impossible by construction.

2. Punishment through strategic stockpiling. When any producer tried to sell outside the CSO, De Beers flooded the market with diamonds from its stockpile, crashing prices below the defector's cost. This was a credible, swift, and devastating punishment mechanism. The threat alone kept producers in line - rational producers anticipated the flood and chose CSO membership over certain price destruction.

3. Control of upstream supply (De Beers owned major mines directly). De Beers was not merely a coordinator - it was itself the largest diamond producer, owning mines in South Africa, Botswana, and Namibia. This gave it both a large captive supply and unmatched ability to flood the market. No other single producer had comparable scale to resist.

4. Diamond demand is driven by non-fungible, occasion-specific purchasing. Diamonds are not consumed and re-sold like oil - they are purchased once for events like engagements and held as jewelry or investment. This one-directional demand flow, combined with De Beers's control of the rough supply, meant there was no secondary market disruption from consumers that could break cartel pricing. De Beers controlled supply; consumers controlled demand; the two did not interact in a way that undermined the cartel's price floor.

The jurisdictional challenge:

US antitrust law - the Sherman Act - applies to conduct that occurs in US commerce or that has a direct, substantial, and reasonably foreseeable effect on US commerce (the "effects doctrine," codified in the Foreign Trade Antitrust Improvements Act). For foreign companies, the US must show that their conduct materially affects US markets.

De Beers's evasion strategy:

De Beers deliberately structured its operations to minimize physical presence in the United States:

• It conducted all diamond sights (sales to sightholders) in London and Lucerne - never on US soil.
• It had no US offices, no US employees, and no US-registered entities.
• Its executives refused to travel to the United States, knowing that setting foot on US soil could subject them personally to arrest and prosecution.
• Legal entities associated with De Beers were incorporated in South Africa and Luxembourg - beyond easy reach of US subpoenas.

By keeping its entire operation offshore, De Beers argued it was not subject to US jurisdiction. Even applying the effects doctrine, proving "direct" effect on US commerce was complicated by the indirect chain: De Beers sold to European sightholders → sightholders sold to US diamond cutters/dealers → eventually reaching US retail consumers. The DOJ struggled to establish that De Beers's conduct directly restrained US trade rather than merely affecting US prices through a chain of independent downstream transactions.

The eventual resolution: After decades of evasion, De Beers settled with the DOJ in 2004 - pleading guilty and paying a $10 million fine - in exchange for the right to operate commercially in the United States without threat of criminal prosecution. The settlement was largely motivated by De Beers's commercial desire to enter the lucrative US retail diamond market, which it had been locked out of by its own evasion strategy.

The two-part test for §2 monopolization:

1. Possession of monopoly power in the relevant market.
2. Willful acquisition or maintenance of that monopoly power through anticompetitive or exclusionary conduct - not through superior product, business acumen, or historical accident.

Element 1 - Monopoly power:

De Beers controlled approximately 80% of world rough diamond supply, and this control was durable over many decades. An 80% market share in the correctly defined relevant market (rough gem diamonds) is strong evidence of monopoly power. The Lerner Index of ~0.33 confirms the firm prices significantly above MC. Element 1 is clearly satisfied.

Element 2 - Conduct analysis:

Legitimate competitive conduct (not exclusionary):

• De Beers directly owning and operating mines - acquiring market share through investment in productive assets is legitimate. Building better mines is precisely the kind of competition antitrust law seeks to encourage.

Exclusionary conduct:

• Exclusive purchasing agreements with independent producers: De Beers required producers who signed with the CSO not to sell to anyone else. This forecloses competition at the supply level - independent dealers and rival distributors cannot access rough diamond supply. This resembles exclusive dealing, which can be exclusionary under §2 when used by a monopolist to maintain its position.
• Predatory flooding of the market: When producers attempted to sell independently, De Beers deliberately flooded the market with stockpiled diamonds to destroy their prices. This is the classic pattern of predatory pricing - pricing below cost (or at a loss on stockpile sales) to discipline or eliminate a competitive threat, then raising prices once the threat is neutralized.
• Stockpiling as a strategic weapon: Maintaining a large buffer stock specifically to punish non-compliance is not a legitimate efficiency - it is a mechanism to coerce market participation and maintain the monopoly.

Conclusion: De Beers satisfies both elements of §2 monopolization. Its market power is substantial and durable, and a meaningful portion of it was maintained through exclusionary conduct (exclusive dealing, predatory punishment) rather than legitimate competitive success.

The legal distinction:

Courts distinguish between:

• "Monopoly by growth or development" - gaining or holding monopoly power through superior efficiency, innovation, or better products. This is lawful under §2.
• "Exclusionary monopoly" - conduct that maintains monopoly power not by being better, but by preventing rivals from competing on the merits. This violates §2.

The key test is whether the conduct would be rational for a competitive firm absent its anticompetitive effect - or whether it only makes sense as a strategy to exclude rivals and preserve monopoly power.

Applying this to De Beers's contracts:

The exclusive purchasing agreements with independent mines went beyond simple supply contracts. Their purpose was not just to secure a reliable input supply (a legitimate efficiency justification for long-term contracts) - it was to ensure that no rival distributor could access rough diamonds at all. A competitive firm buys inputs; a monopolist uses exclusive dealing to foreclose rivals' access to those same inputs.

Key indicators that these contracts were exclusionary:

1. They covered the entire supply market. De Beers sought to bring every significant producer under CSO control, not just enough to meet its own needs. This is the hallmark of exclusionary intent - controlling supply beyond what any legitimate production rationale requires.

2. Paired with punishment. The contracts were reinforced by the market-flooding threat. A legitimate long-term supply contract does not come with a threat to destroy your revenues if you sell to anyone else. The punishment mechanism reveals the contracts' true purpose: monopoly maintenance, not supply security.

3. Foreclosure of the entire input market. By controlling ~80% of rough supply through ownership and contracts, De Beers made it impossible for any rival diamond distributor to exist at meaningful scale. This is foreclosure of the market itself, not competition on the merits.

Conclusion: The contracts crossed from legitimate supply procurement into exclusionary dealing because of their scope (entire market), their purpose (foreclosure), and their enforcement mechanism (predatory punishment). Courts would likely find this satisfies the exclusionary conduct element of §2.

The key difference:

Under US Sherman Act §2, it is not illegal to be a monopoly - only to acquire or maintain monopoly power through anticompetitive conduct. A firm can hold 80% market share indefinitely without violating the law, as long as it did not use exclusionary tactics to get or keep it there. The law requires proof of both monopoly power and exclusionary conduct.

Under EU Article 102, the standard is "abuse of dominant position." Once a firm is found to hold a dominant position (typically inferred from a market share above ~40–50% in EU case law), certain conduct that would be acceptable from a non-dominant firm becomes illegal precisely because the firm is dominant. The EU places a special responsibility on dominant firms not to engage in practices - even ones that might otherwise seem ordinary - that distort competition.

How this affects the De Beers analysis:

• Under US §2: The DOJ must prove both that De Beers has monopoly power (satisfied - 80% share) and that specific conduct (exclusive dealing, predatory flooding) is exclusionary. Conduct that could be characterized as "legitimate business practices" - such as offering producers favorable long-term purchase contracts - is harder to condemn.

• Under EU Article 102: Once De Beers is found dominant (straightforward at 80%), even conduct like offering exclusive supply contracts or managing stockpiles becomes suspect because it reinforces dominance. The EU would not require proof of "predatory intent" - it would scrutinize whether the conduct, regardless of intent, has the effect of excluding rivals or reinforcing De Beers's dominance.

Practical implication: The EU standard would make it significantly easier to bring a case against De Beers. The US standard's requirement to prove both elements - and to show specific exclusionary intent or effect - is more demanding, which partially explains why the DOJ struggled to convict De Beers for decades despite its obvious market dominance.

Applying the SSNIP test:

If a hypothetical monopolist of natural rough diamonds raised prices by 5%, would enough consumers substitute to lab-grown diamonds to make the increase unprofitable?

The answer depends on consumer perception of substitutability, which is genuinely contested:

Arguments for including synthetics (broader market):

• Synthetics are chemically identical - they are the same product at the molecular level.
• At $800/carat vs.$4,000/carat for comparable natural stones, the price gap is enormous. Even a 5% increase on natural diamonds would leave them far more expensive than synthetics.
• For price-sensitive buyers who value the physical diamond but not its provenance, synthetics are clearly a substitute.

Arguments for excluding synthetics (narrow market):

• Consumer surveys consistently show that many buyers - especially for engagement rings - specifically want a natural diamond because of its rarity and romantic symbolism. "A lab-grown diamond" does not carry the same emotional meaning.
• De Beers's own marketing has cultivated this perception for decades. If consumers reject synthetics for engagement purposes regardless of price, they are not demand-side substitutes.
• The relevant question is whether the marginal buyer - the one who determines whether a price increase is profitable - would switch. If even a 20% price gap does not cause switching for engagement ring buyers, a 5% increase certainly won't.

Most likely answer for antitrust purposes: Synthetics probably constitute a separate relevant market, at least for the specific occasion-based purchasing that dominates the high-end diamond market. The SSNIP test would not expand the market to include them, because the emotional and cultural differentiation means consumers would not switch even at the margin.

The paradox for De Beers:

• For legal exposure: A broad market including synthetics helps De Beers. If synthetics are a substitute, De Beers's market share falls dramatically from ~80% to something much lower, potentially below the threshold for monopoly power. De Beers would prefer this definition in court.

• For its business model: Including synthetics as substitutes destroys De Beers's value proposition. If lab-grown diamonds at $800/carat are functionally identical to natural diamonds at$4,000, why buy natural? The very argument that protects De Beers legally (synthetics are a close substitute) simultaneously threatens to commoditize natural diamonds and collapse the price premium on which its entire business depends. De Beers cannot simultaneously argue in court that synthetics dilute its market power and argue to consumers that natural diamonds are irreplaceable.

This is the paradox: the legal defense and the business model are in direct contradiction.

The predatory pricing standard (Brooke Group test in the US):

US courts apply a two-part test for predatory pricing under §2:

1. Prices must be below an appropriate measure of cost (typically average variable cost or marginal cost).
2. The predator must have a dangerous probability of recouping its losses once rivals are eliminated.

Analyzing Lightbox at $800/carat:

*Is $800/carat below cost?* De Beers claimed Lightbox was priced to reflect the actual production economics of lab-grown diamonds - that$800/carat was a sustainable, profitable price given the falling cost of lab-grown production (energy, equipment). If true, pricing at $800/carat is not below cost - it is simply setting a competitive price for a different product with lower production costs than natural diamonds.

Strategic intent vs. legitimate competition: The Lightbox strategy is better understood as price anchoring - a signal to consumers that lab-grown diamonds are mass-market, low-prestige products worth $800, not premium stones comparable to$4,000 natural diamonds. By aggressively entering the lab-grown market at a low price, De Beers simultaneously:

• Caps the price appreciation of lab-grown diamonds.
• Reinforces the price premium of natural diamonds by contrast.
• Prevents lab-grown competitors from establishing a premium market position that could erode natural diamond demand.

Antitrust conclusion: Lightbox is most accurately characterized as a strategic market-positioning move rather than classic predatory pricing. Classic predation requires pricing below cost to eliminate rivals and then raising prices. Here, De Beers may be pricing at cost for lab-grown diamonds while protecting its premium natural diamond segment. This is closer to product differentiation strategy than predation.

However, if evidence emerged that $800/carat is below De Beers's actual production cost for lab-grown stones, and that De Beers intended to recoup losses by eliminating synthetic rivals and then raising lab-grown prices, a predatory pricing claim would be viable. The recoupment requirement would be difficult to satisfy given the many lab-grown producers globally.

Was the $10 million fine adequate?

No - by almost any measure, the fine was grossly inadequate as a deterrent.

De Beers's annual revenues were $5.6 billion. The$10 million fine represents approximately 0.18% of annual revenue - a trivial sum for a company that maintained a global diamond monopoly for nearly a century. From an economic deterrence standpoint, a fine deters illegal conduct only if the expected cost (probability of conviction × fine) exceeds the expected gain from the violation. With decades of successful evasion (low probability of conviction) and a minuscule fine when finally caught, the deterrence calculation strongly favored continued illegal conduct.

Moreover, the $10 million fine was arguably lower than the foregone US market revenues De Beers had sacrificed over decades to avoid prosecution - meaning the settlement rewarded De Beers for its evasion by granting US market access, the very thing it had been trying to obtain.

What remedy would have better served antitrust goals?

Structural remedy: Breaking up the CSO - requiring De Beers to divest its exclusive purchasing agreements with independent producers and allow producers to sell freely on the open market - would have directly addressed the source of De Beers's market power. This would restore competitive supply in the rough diamond market, putting downward pressure on prices for consumers (jewelry manufacturers, retailers, end buyers).

Behavioral remedy limitations: The behavioral restrictions in the settlement were limited and did not fundamentally alter De Beers's ability to control supply through mine ownership and the successor to the CSO. Without structural change, De Beers's ability to exercise market power remained largely intact.

Broader observation: The settlement reflected a pragmatic compromise - the DOJ secured a guilty plea (establishing legal precedent) while De Beers gained commercial access to the US market it wanted. But from a consumer welfare perspective, the settlement failed to restore competition in the diamond market. It resolved the legal proceeding without resolving the underlying competitive problem.