Banks seem to really push credit card use on their customers, seeing all the junk mail, the recruitment stands in malls, campuses and airports, and the various incentives (frequent flyer miles, cash-backs). Why are they doing this? One would think the marginal customer is less profitable, and may even be detrimental to the bottom line as he is more likely to default.
Sumit Agarwal, Sujit Chakravorti, and Anna Lunn look specifically at cash-backs using administrative data and find that a 1 percent increase in cash-back leads to a US$68 increase in spending and US$115 increase in debt in the first quarter. While one can understand this would increase spending, it is puzzling to see the debt increase even more. Why would people substitute debt away from other cards? Indeed debt is not tied to this cash-back. It turns out this comes mostly from people who have previously barely used the card, thus they basically switch allegiance both in spending and debt. A reduction in the interest rate has similar consequences.
Are cash-backs good or bad. This paper shows that they are mostly used to steal customers from other cards. Such competition is good. However, the ones who pay for these rewards are the merchants, who face basically a duopoly and are caught between a rock and a hard place. Ultimately, the consumer ends up paying for these cash-backs through higher prices in the store, and those using cash or debit cards lose out.