An Empirical Model of Subprime Mortgage Default From 2000 to 2007

The turmoil that started with increased defaults in the subprime mortgage market has generated instability in the financial system around the world. To better understand the root causes of this financial instability, we quantify the relative importance of various drivers behind subprime borrowers' decision to default. In our econometric model, we allow borrowers to default either because doing so increases their lifetime wealth or because of short-term budget constraints, treating the decision as the outcome of a bivariate probit model with partial observability. We estimate our model using detailed loan-level data from LoanPerformance and the Case-Shiller home price index. According to our results, one main driver of default is the nationwide decrease in home prices. The decline in home prices caused many borrowers' outstanding mortgage liability to exceed their home value, and for these borrowers default can increase their wealth. Another important driver is deteriorating loan quality: The increase of borrowers with poor credit and high payment to income ratios elevates default rates in the subprime market. We discuss policy implications of our results. Our findings point to flaws in the securitization process that led to the current wave of defaults. Also, we use our model to evaluate alternative policies aimed at reducing the rate of default.

Nearly Optimal Pricing for Multiproduct Firms

In principle, a multiproduct firm can set separate prices for all possible bundled combinations of its products (i.e., "mixed bundling"). However, this is impractical for firms with more than a few products, because the number of prices increases exponentially with the number of products. In this study we show that simple pricing strategies are often nearly optimal -- i.e., with surprisingly few prices a firm can obtain 99% of the profit that would be earned by mixed bundling. Specifically, we show that bundle-size pricing -- setting prices that depend only on the size of bundle purchased -- tends to be more profitable than offering the individual products priced separately, and tends to closely approximate the profits from mixed bundling. These findings are based on an array of numerical experiments covering a broad range of demand and cost scenarios, as well as an empirical analysis of the pricing problem for an 8-product firm (a theater company).

The effect of satellite entry on product quality for cable television

In vertically differentiated markets, the effects of firm entry are contingent upon whether incumbent firms can respond to entry by adjusting product quality in addition to simply lowering prices. Using market-level data, I estimate a structural model of supply and demand for subscription television that takes into account the endogeneity of quality choice. Using counterfactual analysis, I decompose the effect of satellite entry on existing cable into two components: the conventional price response and the effect of endogenous quality adjustments (measured by changes in programming content). Consistent with the empirical observation that cable prices rose during the 1990s and early 2000s "in spite of" increasing competition, I find that raising both price and quality for the most comprehensive subscription package--i.e., competing "head-to-head"--is the rational response to entry by cable systems in markets with relatively homogeneous consumer types. Elsewhere, incumbents respond less aggressively and relegate themselves to being the low-end provider. When an entrant credibly commits to serving consumers with the highest preferences for quality, competition over both price and quality lowers the welfare gains due to entry, relative to pure price competition. In particular, head-to-head competition results in "crowding" of quality choices toward the high end of the market and inefficiently low product differentiation. In such cases, consumers with weak quality preferences may actually become worse off following entry. The evidence also suggests that the observed degradation of the lowest-quality cable tier in many markets during this time period--while commonly seen as an attempt to evade price regulation--may actually have been welfare-enhancing.Supply and demand ; Cable television industry

Bundle-Size Pricing as an Approximation to Mixed Bundling

Multiproduct firms can set separate prices for all possible bundled combinations of its products "mixed bundling"). However, this is impractical for firms with more than a few products, because the number of prices increases exponentially with the number of products. We find that simple pricing strategies are often nearly optimal. Specifically, we show that bundle-size pricing--setting prices that depend only on the size of bundle purchased--tends to be more profitable than offering the individual products priced separately and tends to closely approximate the profits from mixed bundling. (JEL D24, D42, L11, L13, L25)

Differences across originators in CMBS loan underwriting

Differences in the organizational structure of CMBS loan originators may reflect differences in the incentives they face for underwriting risky loans. We treat an originator's type--that is, commercial bank, investment bank, insurance company, finance company, conduit lender, or foreign-owned entity--as a proxy for incentives related to warehousing risk, balance sheet lending, and regulatory constraints. After controlling for observable credit characteristics of over 30,000 loans securitized into CMBS after 1999, we find considerable differences in loan performance across originator types. The results suggest that moral hazard--captured by lack of warehousing risk-negatively affected the quality of loans underwritten by conduit lenders. On the other hand, despite opportunities for adverse selection, balance sheet lenders--commercial banks, insurance companies and finance companies--actually underwrote higher quality loans.Mortgage-backed securities ; Moral hazard