A new model for pro-categories

In this paper we present a new way to construct the pro-category of a category. This new model is very convenient to work with in certain situations. We present a few applications of this new model, the most important of which solves an open problem of Isaksen [Isa] concerning the existence of functorial factorizations in what is known as the strict model structure on a pro-category. Additionally we explain and correct an error in one of the standard references on pro-categories.Comment: Substantial overlap with arXiv:1305.4607. Accepted for publication in the Journal of Pure and Applied Algebra, reference: JPAA-504

Sudden Stops and the Mexican Wave: Currency Crises, Capital Flow Reversals and Output Loss in Emerging Markets.

Sudden Stops are the simultaneous occurence of a currency/balance of payments crisis with a reversal in capital flows (Calvo, 1998). We investigate the output effects of financial crises in emerging markets, focusing on whether sudden-stop crises are a unique phenomenon and whether they entail an especially large and abrupt pattern of output collapse (a "Mexican wave"). Despite an emerging theoretical literature on Sudden Stops, empirical work to date has not precisely identified their occurences nor measured their subsequent output effects in broad samples. Analysis of Sudden Stops may provide the key to understanding why some currency/balance of payments crises entail very large output losses, while others are frequently followed by expansions. Using a panel data set over the 1975-97 period and covering 24 emerging-market economies, we distinguish between the output effects of currency crises, capital inflow reversals, and sudden-stop crises. We find that sudden-stop crises have a large negative, but short-lived, impact on output growth over and above that found with currency crises. A currency crisis typically reduces output by about 2-3 percent, while a Sudden Stop reduces output by and additional 6-8 percent in the year of the crisis. The cumulative output los of a Sudden Stop is even larger, around 13-15 percent over a three-year period. Out model estimates correspond closely to the output dynamics of the "Mexican wave" (such as seen in Mexico in 1995, Turkey in 1994 and elsewhere), and out-of-sample predictions of the model explain the sudden (and seemingly unexpected) collapse in output associated with the 1997-98 Asian Crisis. The empirical results are robust to alternative model specifications, lag structures and using estimation procedures (IV and GMM) that correct for bias associated with simultaneity and estimation of dynamic panel models with country-specific effect.

How Bad Are Twins? Output Costs of Currency and Banking Crises.

We investigate the output effects of severe banking and currency crises in emerging markets, focusing on whether "twin crises" (simultaneous occurrence of currency and banking crises) exist as a unique phenomenon and whether they entail especially large losses. Recent literature, mostly relating to the East Asian crisis, emphasizes the interplay and reinforcement between currency and banking crises, presumably making twin crises particularly damaging to the real economy. Using a panel data set over the 1975-97 period and covering 24 emerging-market economies, we find that twin crises do not contribute any additional (marginal) negative impact on output growth. That is, twin crises do not adversely impact output over and above the independent effects associated with a currency and banking crisis taken together. We find that currency (banking) crises are very damaging, reducing output by about 5-8 (8-10) percent over a two-four year period. The cumulative output loss of both types of crises occurring at the same time is therefore very large, around 13-18 percent, and should alarm policymakers. However, twin crises are "bad" only in that they entail output losses associated with both currency and banking crises, not because there are additional feedback or interactive effects further damaging the economy. This result is robust to alternative model specifications, lag structures and using IV and GMM estimation procedures that correct bias associated with simultaneity and estimation or dynamic panel models with country-specific effects.

Bidding With Securities: Auctions and Security Design

We study security-bid auctions in which bidders compete by bidding with securities whose payments are contingent on the realized value of the asset being sold. Such auctions are commonly used, both formally and informally. In formal auctions, the seller restricts bids to an ordered set, such as an equity share or royalty rate, and commits to a format, such as first or second-price. In informal settings with competing buyers, the seller does not commit to a mechanism upfront. Rather, bidders offer securities and the seller chooses the most attractive bid, based on his beliefs, ex-post. We characterize equilibrium payoffs and bidding strategies for formal and informal auctions. For formal auctions, we examine the impact of both the security design and the auction format. We define a notion of the steepness of a set of securities, and show that steeper securities lead to higher revenues. We also show that the revenue equivalence principle holds for equity and cash auctions, but that it fails for debt (second-price auctions are superior) and for options (a first-price auction yields higher revenues). We then show that an informal auction yields the lowest possible revenues across all possible formal mechanisms. Finally, we extend our analysis to consider the effects of liquidity constraints, different information assumptions, and aspects of moral hazard.