Concerns about missed sales induce merchants to accept card payments.
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Merchants always opt for a card surcharge (levy) over a cash discount (giveaway).
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Surcharging always generates too few card transactions.
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Card surcharges increases welfare if and only if the merchant fee is high.
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The optimal surcharge cap equals the merchant fee minus his convenience benefit.
Abstract
The proliferation of new payment methods on the Internet rekindles the old and unsettled debate about merchants’ incentive and ability to differentiate price according to payment choice. This paper develops an imperfect-information framework for the analysis of platform and social regulation of card surcharging and cash discounting. It makes three main contributions. First, it identifies the conditions under which concerns about missed sales induce merchants to perceive that they must take the card. Second, it derives a set of predictions about cash discounts, card surcharges and platform fees that shed light on existing evidence. Finally, it shows that the optimal regulation of surcharging is related to public policy toward merchant fees and substantially differs from current practice.
