Interchange Fee Market Power Dynamics

1. Introduction

Interchange fees are payments made between participants in payment-card transactions, typically from the card-accepting merchant's acquiring bank to the cardholder's issuing bank. They form an important component of the economics of four-party payment systems.

A simplified transaction looks like:

Cardholder → Merchant
↓
Issuing Bank ↔ Card Network ↔ Acquiring Bank
↓
Merchant

The interchange fee is important because it influences:

merchant service charges;

cardholder fees;

rewards;

issuing-bank incentives;

acquiring-bank economics;

network participation;

payment-method competition.

Competition law therefore becomes concerned when payment networks or banks possess sufficient market power to set, maintain, coordinate or exploit interchange fees.

The central competition-law question is:

When does an interchange fee constitute a legitimate mechanism for balancing a two-sided payment network, and when does it become an instrument for exercising or facilitating market power?

2. Economic Function of Interchange Fees

Interchange fees can perform legitimate economic functions.

A payment network has two principal customer groups:

cardholders, and

merchants.

The network must attract both sides.

For example, a network may use interchange revenue to support:

card issuance;

fraud prevention;

network security;

rewards;

payment innovation;

authentication;

transaction processing.

This creates a two-sided market.

The network may therefore deliberately place more of the cost on merchants while subsidising cardholders.

Consequently, a high interchange fee does not automatically prove market power or anti-competitive conduct.

3. Four-Party Payment Model

The traditional four-party structure consists of:

Issuer

The bank that provides the card to the consumer.

Acquirer

The bank or payment institution serving the merchant.

Card network

The network providing transaction infrastructure and operating rules.

Merchant

The business accepting the card.

The interchange fee generally flows:

Acquirer → Issuer

The merchant ultimately bears the economic burden through the merchant service charge.

4. Why Interchange Fees Create Competition Problems

Interchange fees can raise competition concerns because they may be:

centrally determined;

collectively applied;

difficult for merchants to negotiate;

imposed through network rules;

resistant to competitive pressure;

capable of influencing both sides of the market.

The problem becomes more significant where merchants cannot realistically refuse the payment method because consumers strongly prefer it.

This can produce a form of merchant-side dependency.

5. Market Power in Payment Networks

Market power can arise from:

network effects;

large installed customer base;

merchant acceptance;

consumer familiarity;

switching costs;

interoperability barriers;

brand recognition;

rewards ecosystems.

A payment network becomes more valuable as more participants use it.

This produces:

More cardholders → more merchants → greater network value → more cardholders.

Such network effects can make entry difficult.

6. Two-Sided Market Analysis

Interchange-fee cases cannot always be analysed using a conventional one-sided market model.

The relevant economic question may be:

How does a change in interchange fees affect both cardholders and merchants?

For example:

Higher interchange fee → greater issuer revenue → better card rewards → more consumers use the card.

But simultaneously:

Higher interchange fee → higher merchant costs → merchants potentially raise prices or reduce acceptance.

The competitive effect therefore needs to consider the interdependence of both sides.

7. Case Law: United States v. Visa U.S.A. Inc.

The U.S. litigation concerning Visa and Mastercard is one of the foundational payment-network competition cases.

The U.S. Department of Justice challenged restrictions imposed by major card networks that limited banks' ability to issue competing cards.

Competition principle

Rules that prevent financial institutions from dealing with competing networks can reinforce network market power.

Relevance to interchange fees

A network possessing significant market power may be able to maintain favourable fee structures partly because participating banks cannot freely switch between competing networks.

The case demonstrates that network rules can be as important as explicit pricing decisions.

8. United States v. American Express Co., 838 F.3d 179 (2d Cir. 2016)

This case concerned American Express's anti-steering provisions.

Merchants were restricted from steering customers toward alternative payment systems by offering incentives or otherwise encouraging the use of competing cards.

The Second Circuit held that the relevant market had to account for the two-sided nature of the payment platform.

Importance

The decision recognised that:

consumers + merchants

are economically interconnected sides of the same transaction platform.

Interchange-fee relevance

If merchants cannot steer consumers toward cheaper payment methods, a payment network may face weaker competitive pressure to reduce merchant-facing fees.

9. Ohio v. American Express Co., 585 U.S. 529 (2018)

The U.S. Supreme Court affirmed the importance of considering both sides of a two-sided transaction platform.

The Court treated the payment network as a transaction platform connecting merchants and cardholders.

Key principle

Competitive effects cannot necessarily be assessed by examining only merchant fees.

The analysis must consider:

merchant-side effects;

cardholder-side effects;

network effects;

rewards;

overall transaction-platform output.

Relevance

This is one of the most important authorities for understanding interchange-fee market power.

A payment network might increase merchant fees while simultaneously providing benefits to consumers.

That does not automatically establish an antitrust violation.

10. Mastercard Inc. v Merricks, Case C-587/17

The European Court of Justice considered collective damages claims concerning Mastercard's interchange fees.

The underlying dispute involved allegedly excessive interchange fees imposed through Mastercard's payment system.

Importance

The case illustrates that interchange fees can generate large-scale competitive harm affecting millions of transactions.

Competition relevance

A common fee imposed throughout a payment network can create a common economic impact on merchants and consumers.

The case is especially important for understanding:

damages;

pass-on effects;

collective redress;

widespread market effects of payment-network pricing.

11. Commission v Mastercard Inc., Case C-382/12 P

This is one of the leading EU cases on interchange fees.

The European Commission had challenged Mastercard's multilateral interchange fees.

The Court of Justice considered whether the interchange arrangements could be treated as necessary or ancillary to the operation of the payment system.

Key principle

An agreement may be assessed under competition law even when it contributes to the functioning of a legitimate payment system.

The relevant question is whether the restriction is:

objectively necessary;

proportionate;

sufficiently connected to legitimate system functioning.

Importance

This case demonstrates that payment-system efficiency does not automatically immunise interchange arrangements from Article 101 TFEU scrutiny.

12. Mastercard Inc. v Commission, Case T-111/08

The General Court upheld much of the European Commission's approach to Mastercard's multilateral interchange fees.

The case examined whether Mastercard's interchange arrangements restricted competition and whether efficiencies justified them.

Competition principle

A fee arrangement embedded within a payment network may have restrictive effects even though the underlying payment system provides valuable services.

Relevance

It provides a framework for examining:

fee-setting;

market structure;

network effects;

merchant costs;

efficiencies;

consumer benefits.

13. BIDS v Commission, Case C-209/07

Although not a payment-card case, this case is important for understanding agreements that restrict competition while potentially producing efficiencies.

The Court considered the relationship between restrictive arrangements and legitimate economic objectives.

Interchange-fee relevance

Payment networks frequently argue that interchange fees are necessary to:

balance the two sides of the market;

encourage issuance;

promote card acceptance;

finance network security.

The BIDS principles illustrate why the competition analysis must examine whether restrictions are genuinely necessary and proportionate.

14. Interchange Fees and Collective Price Setting

One of the most important competition questions is:

Who sets the interchange fee?

If competing banks independently negotiate fees, market forces may constrain pricing.

But if a payment network establishes a common multilateral interchange fee applicable across numerous issuers and acquirers, competition concerns become stronger.

The arrangement may eliminate independent fee negotiation between banks.

Thus:

Common fee → reduced bilateral competition → potentially higher merchant costs.

However, the network may argue that a common fee is necessary to make a multi-party payment system function.

15. The "Default Fee" Problem

Multilateral interchange fees often function as default rules.

This matters because banks may otherwise negotiate individually.

A default fee can:

reduce transaction costs;

simplify network operation;

provide predictability.

But it can also become a de facto industry-wide price.

The competition-law question is therefore whether the fee is genuinely necessary for the system or instead operates as a mechanism for suppressing competition.

16. Merchant Bargaining Power

Large merchants may negotiate payment-processing arrangements.

Small merchants may have considerably less bargaining power.

This creates an important distinction between:

large retailers;

small businesses;

online merchants;

marketplaces.

Where acceptance of a card network is commercially indispensable, merchants may have little practical ability to reject high fees.

This can strengthen the economic significance of network market power.

17. No-Surcharge Rules

Some payment networks impose or historically imposed restrictions on merchants charging customers different prices depending on payment method.

Such restrictions can raise competition concerns because they may prevent merchants from signalling the relative cost of different payment methods.

Suppose:

Card transaction cost = ₹X

Bank-transfer cost = ₹Y

If the merchant cannot differentiate prices, consumers may not internalise the higher cost of card payments.

This can weaken consumer-side pressure on the payment network.

18. Anti-Steering Rules

Anti-steering rules prevent merchants from directing consumers toward alternative payment systems.

Examples include restrictions on:

discounts for alternative payment methods;

informing consumers about payment costs;

encouraging bank transfers;

promoting cheaper cards.

These rules can reinforce payment-network market power.

The American Express litigation is therefore highly relevant.

19. Interchange Fees and Rewards

Rewards programs complicate the analysis.

Higher interchange revenue can finance:

cashback;

airline miles;

loyalty programmes;

discounts.

This creates:

Higher interchange → greater issuer revenue → better rewards → greater cardholder demand.

But merchants ultimately bear some of the cost.

The resulting economic question is whether the benefits to cardholders offset the competitive harm imposed on merchants.

20. Pass-Through to Consumers

Merchants may respond to interchange fees by:

raising prices;

reducing discounts;

imposing minimum transaction amounts;

refusing certain cards.

If merchants increase prices for all customers, even consumers paying by cash or bank transfer may bear some of the cost.

Thus interchange fees can have indirect consumer effects.

21. Network Effects and Entry Barriers

A new payment network faces a classic chicken-and-egg problem:

Consumers will not use it without merchants.

But:

Merchants will not accept it without consumers.

Established networks already possess both sides.

This creates substantial entry barriers.

High interchange fees may therefore be sustainable even if merchants dislike them because switching to a smaller network may reduce consumer demand.

22. Interchange Fees and Digital Payments

The issue has expanded beyond traditional cards.

Modern payment ecosystems include:

mobile wallets;

tokenised cards;

digital wallets;

account-to-account payments;

QR payments;

buy-now-pay-later systems;

embedded payment platforms.

Market power may shift from traditional card networks toward digital intermediaries.

23. India: Interchange Economics

In India, the competitive environment is distinctive because payment systems include:

card networks;

banks;

payment aggregators;

digital wallets;

account-to-account systems;

UPI infrastructure.

UPI has substantially altered the competitive landscape by providing a low-cost account-to-account payment mechanism.

This creates an important competitive constraint on card-based payment economics.

However, cards continue to provide particular functions such as:

credit;

rewards;

international acceptance;

deferred payment;

specialised consumer services.

Competition therefore occurs across multiple payment architectures.

24. Interchange Fees and Competition Between Payment Systems

Competition is not necessarily only:

Visa vs Mastercard

or:

one card network vs another.

It may also involve:

cards vs UPI;

cards vs wallets;

cards vs bank transfers;

wallets vs account-to-account payments.

The relevant market must therefore consider substitution.

If merchants can easily switch to another payment mechanism, payment-network market power may be constrained.

If consumers strongly prefer a particular payment instrument, however, merchant-side substitutability may be weaker.

25. Vertical Integration

Payment-network market power can become stronger where the network or affiliated institution controls multiple stages:

Network → issuer → wallet → acquiring → merchant services → data analytics.

Vertical integration may create efficiencies.

But it may also permit:

discriminatory access;

foreclosure;

self-preferencing;

exclusion of competing networks.

Competition authorities therefore need to examine the entire payment ecosystem.

26. Data and Interchange Fees

Payment networks possess large transaction datasets.

These can provide information about:

consumers;

merchants;

transaction volumes;

purchasing patterns;

fraud;

payment behaviour.

If a dominant network uses transaction data to provide additional services, it could develop advantages in:

lending;

advertising;

insurance;

financial analytics.

This raises a broader question of data-driven payment ecosystem dominance.

27. Interchange Fees and Fintech

Fintech firms may depend upon established payment infrastructure.

Examples include:

payment aggregators;

digital wallets;

embedded-finance companies;

merchant platforms.

If incumbents impose discriminatory access conditions, new fintech entrants may face higher costs.

Thus competition policy must consider not merely interchange fees but access to payment infrastructure.

28. Competition-Law Theories of Harm

The principal theories include:

1. Excessive pricing

Whether a dominant network can sustain excessively high fees.

2. Coordinated pricing

Whether banks or networks collectively establish interchange fees.

3. Anti-steering

Whether merchants are prevented from encouraging cheaper payment methods.

4. Exclusion

Whether network rules disadvantage competing payment systems.

5. Raising rivals' costs

Whether fee structures increase the cost of competing payment networks.

6. Foreclosure

Whether network rules prevent entry by alternative payment systems.

7. Leveraging

Whether payment-network power is extended into adjacent financial markets.

29. Efficiency Arguments

Payment networks can legitimately argue that interchange fees:

encourage card issuance;

subsidise consumer participation;

finance fraud protection;

support innovation;

increase acceptance;

maintain network security;

balance two-sided demand.

These arguments are economically important.

The question is whether:

the particular level and structure of the interchange fee is reasonably necessary to achieve those objectives.

30. Possible Regulatory Remedies

Competition authorities or regulators may consider:

interchange-fee caps;

transparency obligations;

restrictions on anti-steering rules;

interoperability requirements;

access obligations;

non-discrimination rules;

data-portability measures;

separation of certain functions;

monitoring of network rules.

A remedy must, however, avoid undermining legitimate network efficiencies.

31. Indian Competition-Law Perspective

Under the Competition Act, 2002, interchange-fee arrangements could potentially implicate:

Section 3

Where competing financial institutions enter arrangements that restrict competition.

Section 4

Where a dominant payment network or intermediary abuses market power.

Combination provisions

Where consolidation creates excessive concentration in payment infrastructure.

The CCI's analysis would need to account for the specialised regulatory framework governing payment systems, including the role of the Reserve Bank of India.

32. Important Analytical Framework

A competition authority examining interchange fees should consider:

A. Market definition

What payment services compete with the relevant network?

B. Two-sided effects

What happens to both consumers and merchants?

C. Network effects

How difficult is it for new networks to achieve scale?

D. Fee-setting mechanism

Who determines the interchange fee?

E. Merchant dependence

Can merchants realistically refuse the payment method?

F. Consumer dependence

Will consumers switch to alternatives?

G. Efficiency

Are fees necessary to balance the platform?

H. Foreclosure

Do network rules prevent alternative payment systems from competing?

33. Comparative Case-Law Principles

34. Emerging Issue: Algorithmic Interchange Fees

Future payment networks may use algorithms to determine:

interchange rates;

merchant risk;

transaction pricing;

fraud-related charges.

This creates new competition concerns.

If multiple competing networks rely on similar automated systems, algorithms may reduce price competition.

The competition question becomes:

Are algorithms independently responding to market conditions, or are they facilitating coordinated pricing?

35. Emerging Issue: Wallet and Ecosystem Control

A dominant technology ecosystem could control:

Device → Wallet → Payment token → Network → Merchant

This creates multiple layers of potential market power.

A device or operating-system provider could potentially:

favour its own wallet;

restrict competing payment applications;

impose transaction fees;

restrict access to NFC or other payment interfaces.

This extends interchange-fee analysis into digital-platform competition law.

36. Conclusion

Interchange fees occupy a unique position in competition law because they are not simply ordinary prices. They are part of the economic architecture of a two-sided payment network.

The leading cases—particularly Mastercard, American Express, and related payment-network litigation—demonstrate that competition analysis must consider both:

merchant-side costs

and

consumer-side benefits.

At the same time, payment networks cannot automatically justify every fee or network rule by invoking network efficiency.

The key competition-law questions are:

Who controls the fee?

How much market power does the network possess?

Can merchants realistically switch?

Can consumers switch?

Do anti-steering rules suppress alternative payment methods?

Are interchange fees necessary to operate the network?

Do network rules prevent entry by competing systems?

Are efficiency benefits passed through to consumers?

The central modern concern is therefore not simply "Are interchange fees high?" but rather whether payment-network architecture allows a powerful intermediary to maintain fees and impose rules that weaken independent competitive pressure. As payments become increasingly digital and ecosystem-based, interchange-fee analysis will increasingly intersect with platform dominance, network effects, data concentration, interoperability and fintech entry barriers.