Price-parity clauses have, until recently, been little discussed in the academic vertical-price-restraints literature. Their growing importance, however, cannot be ignored, and common misconceptions around their use and implementation need to be addressed. While similar in nature to both resale price maintenance and most-favored-nations clauses, the special vertical relationship between sellers and the platform inherent in price-parity clauses leads to distinct economic outcomes. Additionally, with a growing number of lawsuits targeting their use in online platform economies, it is critical to fully understand the economic incentives and outcomes stemming from price-parity clauses.
Vertical price restraints—of which resale price maintenance (RPM) and most favored nation clauses (MFN) are among many—are both common in business and widely discussed in the academic literature. While there remains a healthy debate among academics as to the true competitive effects of these contractual arrangements, the state of U.S. jurisprudence is clear. Since the Supreme Court’s Leegin and State Oil decisions, the use of RPM is not presumed anticompetitive. Their procompetitive and anticompetitive effects must instead be assessed under a “rule of reason” framework in order to determine their legality under antitrust law. The competitive effects of MFN are also generally analyzed under the rule of reason.
Distinct from these two types of clauses, however, are price-parity clauses (PPCs). A PPC is an agreement between a platform and an independent seller under which the seller agrees to offer their goods on the platform for their lowest advertised price. While sometimes termed “platform MFNs,” the economic effects of PPCs on modern online-commerce platforms are distinct.
This commentary seeks to fill a hole in the PPC literature left by its current focus on producers that sell exclusively nonfungible products on various platforms. That literature generally finds that a PPC reduces price competition between platforms. This finding, however, is not universal. Notably absent from the discussion is any concept of multiple sellers of the same good on the same platform. Correctly accounting for this oversight leads to the conclusion that PPCs generally are both efficient and procompetitive.
In a pair of lawsuits filed in California and the District of Columbia, Amazon has come under fire for its restrictions around pricing. These suits allege that Amazon’s restrictive PPCs harm consumers, arguing that sellers are penalized when the price for their good on Amazon is higher than on alternative platforms. They go on to claim that these provisions harm sellers, prevent platform competition, and ultimately force consumers to pay higher prices. The true competitive result of these provisions, however, is unclear.
That literature that does exist on the effects these provisions have on the competitive outcomes of platforms in online marketplaces falls fundamentally short. Jonathan Baker and Fiona Scott Morton (among others) fail to differentiate between PPCs and MFN clauses. This distinction is important because, while the impacts on consumers may be similar, the mechanisms by which the interaction occurs is not. An MFN provision stipulates that a supplier—when working with several distributors—must offer its goods to one particular distributor at terms that are better or equal to those offered to all other distributors.
PPCs, on the other hand, are agreements between sellers and platforms to ensure that the platform’s buyers have access to goods at better or equal terms as those offered the same buyers on other platforms. Sellers that are bound by a PPC and that intend to sell on multiple platforms will have to price uniformly across all platforms to satisfy the PPC. PPCs are contracts between sellers and platforms to define conduct between sellers and buyers. They do not determine conduct between sellers and the platform.
A common characteristic of MFN and PPC arrangements is that consumers are often unaware of the existence of either clause. What is not common, however, is the outcomes that stem from their use. An MFN clause only dictates the terms under which a good is sold to a distributor and does not constrain the interaction between distributors and consumers. While the lower prices realized by a distributor may be passed on as lower prices for the consumer, this is not universally true. A PPC clause, on the other hand, constrains the interactions between sellers and consumers, necessitating that the seller’s price on any given platform, by definition, must be as low as the price on all other platforms. This leads to the lowest prices for a given good in a market.
The fundamental oversight in the literature is any discussion of intra-platform competition in the market for fungible goods, within which multiple sellers sell the same good on multiple platforms. Up to this point, all the discussion surrounding PPCs has centered on the Booking.com case in the European Union.
In Booking.com, the primary platform, Booking.com, instituted price-parity clauses with sellers of hotel rooms on its platform, mandating that they sell rooms on Booking.com for equal to or less than the price on all other platforms. This pricing restriction extended to the hotel’s first-party website as well.
In this case, it was alleged that consumers were worse off because the PPC unambiguously increased prices for hotel rooms. This is because, even if the hotel was willing to offer a lower price on its own website, it was unable to do so due to the PPC. This potential lower price would come about due to the low (possibly zero cost) commission a hotel must pay to sell on its own website. On the hotel’s own website, the room could be discounted by as much as the size of the commission that Booking.com took as a percentage of each sale. Further, if a competing platform chose to charge a lower commission than Booking.com, the discount could be the difference in commission rates.
While one other case, E-book MFN, is tangentially relevant, Booking.com is the only case where independent third-party sellers list a good or service for sale on a platform that imposes a PPC. While there is some evidence of harm in the market for the online booking of hotel rooms, however, hotel-room bookings are not analogous to platform-based sales of fungible goods. Sellers of hotel rooms are unable to compete to sell the same room; they can sell similarly situated, easily substitutable rooms, but the rooms are still non-fungible.
In online commerce, however, sellers regularly sell fungible goods. From lip balm and batteries to jeans and air filters, a seller of goods on an e-commerce site is among many similarly situated sellers selling nearly (or perfectly) identical products. These sellers not only have to compete with goods that are close substitutes to the good they are selling, but also with other sellers that offer an identical product.
Therefore, the conclusions found by critics of Booking.com’s PPC do not hold when removing the non-fungibility assumption. While there is some evidence that PPCs may reduce competition among platforms on the margin, there is no evidence that competition among sellers on a given platform is reduced. In fact, the PPC may increase competition by forcing all sellers on a platform to play by the same pricing rules.
We will delve into the competitive environment under a strict PPC—whereby sellers are banned from the platform when found to be in violation of the clause—and introduce the novel (and more realistic) implicit PPC, whereby sellers have incentive to comply with the PPC, but are not punished for deviation. First, however, we must understand the incentives of a seller not bound by a PPC.
Competition by sellers not bound by price-parity clauses
An individual seller in this market chooses to sell identical products at different prices across different platforms, given that the platforms may choose various levels of commission per sale. To sell the highest number of units possible, there is an incentive for sellers to steer customers to platforms that charge the lowest commission, and thereby offer the seller the most revenue possible.
Since the platforms understand the incentive to steer consumers toward low-commission platforms to increase the seller’s revenue, they may not allocate resources toward additional perks, such as free shipping. Platforms may instead compete vigorously to reduce costs in order offer the lowest commissions possible. In the long run, this race to the bottom might leave the market with one dominant and ultra-efficient naturally monopolistic platform that offers the lowest possible commission.
While this sounds excellent for consumers, since they get the lowest possible prices on all goods, this simple scenario does not incorporate non-price factors into the equation. Free shipping, handling, and physical processing; payment processing; and the time spent waiting for the good to arrive are all additional considerations that consumers factor into the equation. For a higher commission, often on the seller side, platforms may offer a number of these perks that increase consumer welfare by a greater amount than the price increase often associated with higher commissions.
In this scenario, because of the under-allocation of resources to platform efficiency, a unified logistics market may not emerge, where buyers are able to search and purchase a good; sellers are able to sell the good; and the platform is able to facilitate the shipping, processing, and handling. By fragmenting these markets—due to the inefficient allocation of capital—consumer welfare is not maximized. And while the raw price of a good is minimized, the total price of the transaction is not.
Competition by sellers bound by strict price-parity clauses
In this scenario, each platform will have some version of a PPC. When the strict PPC is enforced, a seller is restricted from selling on that platform when they are found to have broken parity. Sellers choose the platforms on which they want to sell based on which platform may generate the greatest return; they then set a single price for all platforms. The seller might then make higher returns on platforms with lower commissions and lower returns on platforms with higher commissions. Fundamentally, to sell on a platform, the seller must at least cover its marginal cost.
Due to the potential of being banned for breaking parity, sellers may have an incentive to price so low that, on some platforms, they do not turn a profit (due to high commissions) while compensating for those losses with profits earned on other platforms with lower commissions. Alternatively, sellers may choose to forgo sales on a given platform altogether if the marginal cost associated with selling on the platform under parity is too great.
For a seller to continue to sell on a platform, or to decide to sell on an additional platform, the marginal revenue associated with selling on that platform must outweigh the marginal cost. In effect, even if the commission is so high that the seller merely breaks even, it is still in the seller’s best interest to continue on the platform; only if the seller is losing money by selling on the platform is it economically rational to exit.
Within the boundaries of the platform, sellers bound by a PPC have a strong incentive to vigorously compete. Additionally, they have an incentive to compete vigorously across platforms to generate the highest possible revenue and offset any losses from high-commission platforms.
Platforms have an incentive to vigorously compete to attract buyers and sellers by offering various incentives and additional services to increase the quality of a sale. Examples of such “add-ons” include fulfilment and processing undertaken by the platform, expedited shipping and insured shipping, and authentication services and warranties.
Platforms also have an incentive to find the correct level of commission based on the add-on services that they provide. A platform that wants to offer the lowest possible prices might provide no or few add-ons and charge a low commission. Alternatively, the platform that wants to provide the highest possible quality may charge a high commission in exchange for many add-ons.
As the value that platforms can offer buyers and sellers increases, and as sellers lower their prices to maintain or increase sales, the quality bestowed upon consumers is likely to rise. Competition within the platform, however, may decline. Highly efficient sellers (those with the lowest marginal cost) may use strict PPCs—under which sellers are removed from the platform for breaking parity—to price less-efficient sellers out of the market. Additionally, efficient platforms may be able to price less-efficient platforms out of the market by offering better add-ons, starving the platforms of buyers and sellers in the long run.
Even with the existence of marginally higher prices and lower competition in the marketplace compared to a world without price parity, the marginal benefit for the consumer is likely higher. This is because the add-on services used by platforms to entice buyers and sellers to transact on a given platform, over time, cost less to provide than the benefit they bestow. Regardless of whether every single consumer realizes the full value of such added benefits, the likely result is a level of consumer welfare that is greater under price parity than in its absence.
Implicit price parity: The case of Amazon
Amazon’s price-parity-policy conditions access to some seller perks on the adherence to parity, guiding sellers toward a unified pricing scheme. The term best suited for this type of policy is an “implicit price parity clause” (IPPC). Under this system, the incentive structure rewards sellers for pricing competitively on Amazon, without punishing alternative pricing measures. For example, if a seller sets prices higher on Amazon because it charges higher commissions than other platforms, that seller will not eligible for Amazon’s Buy Box. But they are still able to sell, market, and promote their own product on the platform. They still show up in the “other sellers” dropdown section of the product page, and consumers can choose that seller with little more than a scroll and an additional click.
While the remainder of this analysis focuses on the specific policies found on Amazon’s platform, IPPCs are found on other platforms, as well. Walmart’s marketplace contains a similar parity policy along with a similarly functioning “buy” box. eBay, too, offers a “best price guarantee,” through which the site offers match the price plus 10% of a qualified competitor within 48 hours. While this policy is not identical in nature, it is in result: prices that are identical for identical goods across multiple platforms.
Amazon’s policy may sound as if it is picking winners and losers on its platform, a system that might appear ripe for corruption and unjustified self-preferencing. But there are several reasons to believe this is not the case. Amazon has built a reputation of low prices, quick delivery, and a high level of customer service. This reputation provides the company an incentive to ensure a consistently high level of quality over time. As Amazon increases the number of products and services offered on its platform, it also needs to devise ways to ensure that its promise of low prices and outstanding service is maintained.
This is where the Buy Box comes in to play. All sellers on the platform can sell without utilizing the Buy Box. These transactions occur either on the seller’s own storefront, or by utilizing the “other sellers” portion of the purchase page for a given good. Amazon’s PPC does not affect the way that these sales occur. Additionally, the seller is free in this type of transaction to sell at whatever price it desires. This includes severely under- or overpricing the competition, as well as breaking price parity. Amazon’s policies do not directly determine prices.
The benefit of the Buy Box—and the reason that an IPPC can be so effective for buyers, sellers, and the platform—is that it both increases competition and decreases search costs. For sellers, there is a strong incentive to compete vigorously on price, since that should give them the best opportunity to sell through the Buy Box. Because the Buy Box is algorithmically driven—factoring in price parity, as well as a few other quality-centered metrics (reviews, shipping cost and speed, etc.)—the featured Buy Box seller can change multiple times per day.
Relative prices between sellers are not the only important factor in winning the Buy Box; absolute prices also play a role. For some products—where there are a limited number of sellers and none are observing parity or they are pricing far above sellers on other platforms—the Buy Box is not displayed at all. This forces consumers to make a deliberate choice to buy from a specific seller as opposed to from a preselected seller. In effect, the Buy Box’s omission removes Amazon’s endorsement of the seller’s practices, while still allowing the seller to offer goods on the platform.
For consumers, this vigorous price competition leads to significantly lower prices with a high level of service. When a consumer uses the Buy Box (as opposed to buying directly from a given seller), Amazon is offering an assurance that the price, shipping, cost, speed, and service associated with that seller and that good is the best of all possible options. Amazon is so confident with its algorithm that the assurance is backed up with a price guarantee; Amazon will match the price of relevant competitors and, until 2021, would foot the bill for any price drops that happened within seven days of purchase.
For Amazon, this commitment to low prices, high volume, and quality service leads to a sustained strong reputation. Since Amazon has an incentive to attract as many buyers and sellers as possible, to maximize its revenue through commissions on sales and advertising, the platform needs to carefully curate an environment that is conducive to repeated interactions. Buyers and sellers come together on the platform knowing that they are going to face the lowest prices, highest revenues, and highest level of service, because Amazon’s implicit price-parity clause (among other policies) aligns incentives in just the right way to optimize competition.
In some ways, an implicit price-parity clause is the Goldilocks of vertical price restraints.
Without a price-parity clause, there is little incentive to invest in the platform. Yes, there are low prices, but a race to the bottom may tend to lead to a single monopolistic platform. Additionally, consumer welfare is not maximized, since there are no services provided at an efficient level to bring additional value to buyers and sellers, leading to higher quality-adjusted prices.
Under a strict price-parity clause, there is a strong incentive to invest in the platform, but the nature of removing selling rights due to a violation can lead to reduced price competition. While the quality of service under this system may be higher, the quality-adjusted price may remain high, since there are lower levels of competition putting downward pressure on prices.
An implicit price-parity clause takes the best aspects of both no PPC and strict PPC policies but removes the worst. Sellers are free to set prices as they wish but have incentive to comply with the policy due to the additional benefits they may receive from the Buy Box. The platform has sufficient protection from free riding due to the revocation of certain services, leading to high levels of investment in efficient services that increase quality and decrease quality-adjusted prices. Finally, consumers benefit from the vigorous price competition for the Buy Box, leading to both lower prices and higher quality-adjusted prices when accounting for the efficient shipping and fulfilment undertaken by the platform.
Current attempts to find an antitrust violation associated with PPCs—both implicit and otherwise—are likely misplaced. Any evidence gathered on the market will probably show an increase in consumer welfare. The reduced search costs on the platforms alone could outweigh any alleged increase in price, not to mention the time costs associated with rapid processing and shipping.
Further, while there are many claims that PPC policies—and high commissions on sales—harm sellers, the alternative is even worse. The only credible counterfactual, given the widespread permeation of PPC policies, is that all sellers on the Internet only sell through their own website. Not only would this increase the cost for small businesses by a significant margin, but it would also likely drive many out of business. For sellers, the benefit of a platform is access to a multitude (in some cases, hundreds of millions) of potential consumers. To reach that number of consumers on its own, every single independent seller would have to employ a team of marketers that rivals a Fortune 500 company. Unfortunately, the value proposition is not on its side, and until it is, platforms are the only viable option.
Before labeling a specific contractual obligation as harmful and anticompetitive, we need to understand how it works in the real world. To this point, there has been insufficient discussion about the intra-platform competition that occurs because of price-parity clauses, and the potential consumer-welfare benefits associated with implicit price-parity clauses. Ideally, courts, regulators, and policymakers will take the time going forward to think deeply about the costs and benefits associated with the clauses and choose the least harmful approach to enforcement.
Ultimately, consumers are the ones who stand to lose the most as a result of overenforcement. As always, enforcers should keep in mind that it is the welfare of consumers, not competitors or platforms, that is the overarching concern of antitrust.