In economics, price discrimination is a neutral term. It describes any case where the same product sells to different buyers at different prices, for reasons other than cost. Matinee tickets, senior discounts, bulk packs and member prices all qualify. The law steps in only in narrow cases, and loyalty programs sit close to the middle of the topic.
What is price discrimination?
Price discrimination means charging different buyers different prices for the same good, when cost does not explain the gap. A. C. Pigou sorted it into three degrees in his book The Economics of Welfare (Pigou). A 2015 report by the White House Council of Economic Advisers (CEA) used a plainer name: differential pricing (CEA, 2015).
The aim is to charge each buyer closer to what that buyer will pay. A seller with one price leaves money on the table twice. Some buyers would have paid more, and some who would have paid a little less walk away. The CEA report says the main benefit is that, when sellers have some market power, differential pricing expands the size of the market (CEA, 2015).
What are the three degrees of price discrimination?
Pigou sorted the practice into three degrees. In the first, each unit sells at the most its buyer will pay, and no surplus is left to the buyer. In the second, the seller sets a few price bands, and each buyer pays the band just below what they would pay. In the third, the seller splits customers into groups “separated from one another more or less by some practicable mark” and charges each group its own price (Pigou).
The CEA gives each degree a modern face. Personalized pricing, or first degree, means a different price for every buyer. Quantity discounts, or second degree, mean the price per unit falls as you buy more, like popcorn at the movies. Third degree means different prices for different groups, as with discounts for senior citizens (CEA, 2015).
| Degree | How the price is set | Everyday example | Loyalty program form |
|---|---|---|---|
| First | A separate price for each buyer, at or near what that buyer will pay | A negotiated car price | One-to-one offers built from a member’s own history |
| Second | Price falls with quantity or version, and buyers sort themselves | Large popcorn, bulk packs | Spend thresholds, tier benefits, points multipliers |
| Third | A separate price for each group the seller can identify | Senior and student discounts | Member prices that differ from the shelf price |
Second degree needs no data about the buyer, because buyers pick their own band. Third degree needs a mark that sorts people, such as an ID card, a student card or a loyalty number. First degree needs the most data of all.
What conditions does price discrimination need?
Pigou named two conditions. No unit sold in one market can be moved to another market, and no unit of demand can move either (Pigou). If cheap buyers can resell to dear ones, the split collapses. If dear buyers can pose as cheap ones, it collapses just the same.
The CEA lists the practical hurdles. Sellers must first figure out what customers are willing to pay. Competition limits how far a price can rise, and companies need to prevent resale. Last, a seller using personal prices must take care not to alienate buyers who see the tactic as unfair (CEA, 2015).
A loyalty number solves the first two problems at once. It identifies the buyer at checkout, and a member price is usable only by the person who scans the number. That makes a loyalty number a near-ideal mark for pricing by group.
Is price discrimination good or bad for consumers?
It cuts both ways. The CEA’s example is the matinee. Cheap afternoon tickets let large families and fans on a tight budget see a show. Ban them, the report argues, and a theater could keep prices high and leave seats empty. The report also lists costs. Firms sometimes degrade a product on purpose to sort buyers into price groups, and differential pricing moves value from consumers to shareholders (CEA, 2015).
UK supermarket member prices got a hard test in 2024. The Competition and Markets Authority (CMA) checked about 50,000 loyalty priced products. It found that 92% gave a real saving on the usual price in the same store. At the five chains it studied, members saved 17% to 25% on average (CMA, 2024).
The same review found gaps in access. Some supermarkets could do more for people without smartphones and for under 18s, who can find loyalty prices hard to reach (CMA, 2024). A member price only works as a fair discount if the people it targets can join.
Is price discrimination illegal under the Robinson-Patman Act?
Usually not. The US law on point is the Robinson-Patman Act. It bars sellers from charging different prices to “different purchasers of commodities of like grade and quality” (15 U.S.C. 13). The ban applies only where the effect could be to cut competition or build a monopoly. The FTC says price gaps are generally lawful. That holds most clearly when they reflect the cost of serving each buyer, or match a rival’s offer (FTC).
The FTC lists the tests a claim must meet. The Act covers commodities and purchases. Services and leases fall outside it. The goods must be of like grade and quality. There must be sales to at least two buyers at about the same time, and a reasonable chance of harm to competition (FTC).
The statute builds in defenses. Its text allows price gaps that only reflect differences in the cost of making, selling or delivering the goods. It allows a lower price made in good faith to meet a competitor’s equally low price. It also allows price changes for changing market conditions, such as perishable goods about to spoil or seasonal goods going out of date (15 U.S.C. 13).
The Act is back in use. In October 2026, the FTC announced a settlement of the case it brought in 2024 against Southern Glazer’s Wine and Spirits. It called that case its first Robinson-Patman enforcement action in a generation. The complaint alleged that independent retailers paid more than chains such as Total Wine, Walmart and Kroger for identical bottles (FTC, 2026). None of this is legal advice.
How do loyalty programs use price discrimination?
Loyalty programs were among the first places where data set a personal price. The CEA report says they gave big data some of its first uses in personal pricing. A member shares some details and agrees to have purchases tracked. In return, the member gets perks such as free flights, or price cuts on certain grocery items (CEA, 2015).
Most programs use all three degrees. Member prices are third degree, with the loyalty number as the mark. Tiers and spend thresholds are second degree, because members sort themselves by how much they buy. Targeted offers push toward first degree. New York now requires a disclosure next to any price set by an algorithm using personal data (N.Y. Gen. Bus. Law 349-a).
For illustration, a grocer sells a coffee that costs it $5. At $10, 400 shoppers buy it. At $8 for everyone, 700 buy. Profit is $2,000 at $10 and $2,100 at $8. Now the grocer keeps $10 on the shelf and offers $8 to members. Of the 400 full-price buyers, 300 join to get the deal. Another 300 new buyers join too. Sales are 100 at $10 and 600 at $8, for $2,300 of profit.
The leak is the 300 members who would have paid $10. Each one costs $2 in margin. Measuring that leak is the job of incrementality testing, and our guide to loyalty personalization covers how to aim offers at the buyers they actually move.
Frequently asked questions
Is a senior or student discount price discrimination?
Yes, it is third-degree price discrimination: a lower price for a group the seller can identify. The CEA report uses discounts for senior citizens as its example of third degree (CEA, 2015). The ID card is the mark that keeps other buyers from claiming the price.
What is the difference between price discrimination and dynamic pricing?
Price discrimination varies the price by buyer, and dynamic pricing varies it by conditions such as demand or time. New York law defines dynamic pricing as “pricing that fluctuates dependent on conditions” (N.Y. Gen. Bus. Law 349-a). When an algorithm uses personal data to set it, the two overlap.
Does the Robinson-Patman Act apply to services?
No. The FTC says the Act applies to commodities, but not to services, and to purchases, but not to leases (FTC). Other laws still apply to how services are priced.
Why do sellers need to stop resale?
Resale undoes the price gap. If buyers who pay less can sell to buyers who pay more, the high price disappears. Pigou made it a condition that no unit sold in one market can move to another (Pigou). The CEA lists preventing resale as one of the practical hurdles (CEA, 2015).
Are supermarket loyalty prices real discounts?
In the UK review, almost all were. The CMA found 92% of around 50,000 loyalty priced products offered a genuine saving against the usual price in the same store (CMA, 2024). It also found loyalty prices were not always the cheapest option in the market, so shopping around still pays.