Final answer:
Credit card interchange fees or swipe fees are often negotiable for merchants with high-volume transactions. An above-equilibrium interest rate may prompt card companies to lower these fees to attract more customers. Regulatory interventions can also lead to fee adjustments for merchants.
Step-by-step explanation:
The portion of credit card fees that might be negotiated downward based on higher merchant volume levels typically includes the interchange fees or swipe fees. These are fees that credit card processors charge merchants for processing transactions. Large volume merchants often have the negotiating power to request reduced rates from credit card companies, as they present a more significant portion of the business.
When a situation arises with an above-equilibrium interest rate, credit card firms may be inclined to reduce the fees they charge in an effort to attract f more customers and balance supply with demand. Additionally, in some cases, regulatory actions, as seen with the Justice Department's rulings against certain practices by American Express and Mastercard, can also influence the ability of merchants to secure better terms based on the volume of transactions they process.