Interest-free promotions are a prevalent strategy employed by credit card lenders to attract new customers, yet the research exploring their effects on both consumers and lenders remains relatively sparse. The process of selecting an optimal promotion strategy is intricate, involving the determination of an interest-free period duration and promotion-availability window, all within the context of competing offers, fluctuating market dynamics, and complex consumer behaviour. In this paper, we introduce an agent-based model that facilitates the exploration of various credit card promotions under diverse market scenarios. Our approach, distinct from previous agent-based models, concentrates on optimising promotion strategies and is calibrated using benchmarks from the UK credit card market from 2019 to 2020, with agent properties derived from historical distributions of the UK population from roughly the same period. We validate our model against stylised facts and time-series data, thereby demonstrating the value of this technique for investigating pricing strategies and understanding credit card customer behaviour. Our experiments reveal that, in the absence of competitor promotions, lender profit is maximised by an interest-free duration of approximately 12 months while market share is maximised by offering the longest duration possible. When competitors do not offer promotions, extended promotion availability windows yield maximum profit for lenders while also maximising market share. In the context of concurrent interest-free promotions, we identify that the optimal lender strategy entails offering a more competitive interest-free period and a rapid response to competing promotional offers. Notably, a delay of three months in responding to a rival promotion corresponds to a 2.4% relative decline in income.

翻译：免息促销是信用卡贷方吸引新客户的常用策略，但探讨其对消费者和贷方影响的研究仍相对匮乏。选择最优促销策略的过程复杂，涉及免息期时长和促销可用窗口的确定，且需考虑竞争性方案、波动的市场动态及复杂的消费者行为。本文提出一种基于Agent的模型，用于探索不同市场情景下的各类信用卡促销。与以往基于Agent的模型不同，我们的方法侧重于优化促销策略，并依据2019至2020年英国信用卡市场的基准进行校准，其中Agent属性源自大致相同时期英国人口的历史分布。我们通过典型事实和时间序列数据验证模型，从而展示了该技术在研究定价策略和理解信用卡客户行为方面的价值。实验表明，在缺乏竞争对手促销的情况下，贷方利润在免息期约为12个月时最大化，而市场份额则在提供最长期限时达到峰值。当竞争对手不提供促销时，延长促销可用窗口可使贷方实现利润最大化并同时提升市场份额。在同步免息促销的背景下，我们发现贷方的最优策略是提供更具竞争力的免息期，并对竞争对手的促销方案迅速响应。值得注意的是，对竞争对手促销延迟三个月响应将导致收入相对下降2.4%。