Private Information and Price Regulation in the US Credit Card Market

Q1. What did the CARD Act restrict, and how large was the pre-Act practice it curtailed?

Before the CARD Act, lenders raised borrowers’ interest rates in response to new information about risk and demand on 48–54% of borrowing accounts at least once per year; the Act’s repricing restrictions drove this incidence to nearly zero and immediately compressed the interquartile range of interest rates across accounts within a credit-score tier from about 7.5 percentage points to about 5 percentage points — a one-third reduction in price dispersion. The pricing of emergent risk (risk revealed after account opening) was nearly indistinguishable from the pricing of origination risk before the Act (both approximately 30 basis points per 10-point FICO difference); after the Act, emergent risk was priced at only about 7 basis points per 10 FICO points — less than one-third as much — while origination risk remained priced at 26 basis points.

Q2. How are private information types identified and what do they reveal about adverse selection?

Private information types ψ are identified from the equilibrium pricing of mature accounts: the paper exploits portfolio-wide repricing events (where a lender raises rates on all accounts in a segment simultaneously) as quasi-experimental price variation to estimate price sensitivities γ via 2SLS, then inverts the lender first-order conditions to recover residual default-risk types orthogonal to observed credit scores. The Chiappori–Salanié bivariate probit test on simulated borrowing choices and default outcomes confirms adverse selection on new accounts: the estimated correlation of unobservables is 0.104, and within each credit-score group the correlation between private type and borrowing utility is at least 0.4 — meaning the highest-risk private types also have the strongest demand for credit.

Q3. What does the structural model say about markups and their source?

Estimated pre-CARD-Act markups exceed 40% for the median-risk subprime consumer; the high markups reflect a combination of switching costs (setup costs κ averaging $86.5–$89.7 per account for the lowest FICO groups), high borrowing utility δ among high-risk types (averaging 22.9 at FICO 580–599, falling to 3.3 at FICO 780–799), and lenders’ exploitation of private information about which borrowers have low price sensitivity. Setup costs are substantially larger than liquidity costs (costs of paying off existing balances), consistent with prior findings on adjustment costs in financial markets; new-account acquisition costs are increasing in credit score, consistent with lenders making larger offers to attract higher-quality borrowers.

Q4. What happens to prices under the CARD Act restrictions, and why does partial unraveling occur only for deep subprime?

Among deep subprime (FICO 580–599), the Act induces near-complete pooling at roughly 50% APR annualized for all private types; the safest private types exit the market as they are pooled with riskier peers, whose higher costs push prices further up — a textbook Akerlof unraveling spiral — and over 30% of the privately safest subprime borrowers face prices that newly exceed their willingness to pay. At higher credit scores (e.g., FICO 680–699), nearly all private types face lower prices because the mark-up compression dominates; at FICO 780+, all private types face lower or unchanged prices. Average traded prices fall at all credit score levels because: (1) consumers who exit were paying lower prices than those who stay, and (2) borrowers locked into favorable rates retain them as their types worsen.

Q5. What are the consumer surplus gains, and what drives them?

Consumer surplus rises at all credit scores — by approximately $600 for subprime consumers and by over $1,000 for prime and superprime consumers — with the gain coming from two sources of roughly equal magnitude: markup compression (a transfer from lender profits to consumer surplus) and the insurance value of rate lock-in for consumers whose default risk deteriorates. The insurance channel is most important for superprime borrowers, who are most likely to lock in favorable pricing and to experience type migration over the life of a relationship; the direct pecuniary markup gains dominate for subprime borrowers. Even absent any insurance value, the surplus gains from markup compression alone (a few hundred dollars) are comparable to prior reduced-form estimates of the Act’s price effects.

Q6. Why were high pre-CARD-Act markups necessary for the surplus gains?

In a counterfactual where pre-CARD-Act markets are perfectly competitive (marginal-cost pricing), imposing the CARD Act restrictions causes complete market unraveling: all prices exceed 150% APR, virtually no consumers borrow, and surplus per consumer falls by $100–$600 depending on credit score. With only modestly higher price sensitivity (one bootstrapped standard error larger than the point estimate), unraveling occurs at all credit score tiers and total surplus falls throughout the market. The intuition is that with zero markups, lenders have no cushion to absorb adverse selection costs; restricting risk-based repricing immediately makes lending unprofitable for any pooled price, triggering exit cascades that the pre-CARD-Act markup buffer prevented.

Q7. What is the adverse retention finding and its magnitude?

After the Act, lenders face adverse retention on mature accounts: for every 100 basis points by which emergent risk is priced below origination risk, the quarterly hazard of attrition from borrowing falls by 0.7 percentage points — meaning newly risky borrowers are less likely to leave while newly safe borrowers are more likely to leave. This is precisely the dynamics consistent with Akerlof adverse selection: the Act’s restriction on emergent-risk pricing reduces the signal lenders can use to retain safe borrowers selectively, degrading the quality of each lender’s continuing portfolio.

Q8. What private information rents existed before the Act?

Before the CARD Act, lenders exploited private information about borrowers’ demand characteristics: accounts that engaged in over-limit transactions or brief delinquencies (less than 30 days late) received median price increases of 6.9 and 15.5 percentage points annualized respectively, and 12-month revenue yields on these accounts rose by over 50% relative to baseline accounts, generating sustained higher returns despite higher charge-off risk. The revenue yield increase is not transitory; it persists for at least 12 months, and the returns figures confirm these behaviors reveal not just higher costs but also lower price sensitivity — enabling lenders to extract information rents.

Key concepts

private information type (ψ) : in the model’s notation, a consumer’s residual risk and demand characteristic that is known to the consumer and revealed to the incumbent lender over time through account behavior, but not observed by competing lenders or at the time of account opening; identified from equilibrium pricing using the assumption of price-invariant default.

emergent risk : default risk that becomes observable to the lender after account origination, in contrast to origination risk visible at account opening; the CARD Act restricted repricing in response to emergent risk while leaving origination-risk pricing unrestricted.

adverse retention : the post-CARD-Act phenomenon in which borrowers who become higher-risk are less likely to attrite (because their pricing is not raised) while borrowers who become lower-risk are more likely to leave (because their favorable pricing is no longer reinforced); the paper estimates a 0.7 percentage point drop in quarterly attrition hazard per 100 basis points of under-pricing of emergent risk.

insurance value of rate lock-in : the welfare benefit to consumers from knowing that an adverse draw of their risk type will not trigger a price increase; quantified by comparing actual surplus gains with gains in a counterfactual where types are perfectly persistent (eliminating the demand for insurance); roughly equal in magnitude to the direct markup compression gains.

market unraveling : the Akerlof-style exit spiral in which pooling raises prices, inducing exit by low-risk types, which raises the average cost of the remaining pool, which raises prices further; in the paper’s estimates this is severe only among deep subprime (FICO below 620) and would have been universal had pre-CARD-Act markups been zero.