Bank Failure: Evidence from the Colombia Financial Crisis

This paper identifies the main bank specific determinants of bank failure during the financial crisis in Colombia using duration analysis. Using partial likelihood estimation, it shows that the process of failure of financial institutions during that period can be explained by differences in financial health and prudence across institutions. The capitalization ratio is the most significant indicator explaining bank failure. Increases in this ratio lead to a reduction in the hazard rate of failure at any given moment in time. Of special relevance, this ratio exhibits a non-linear component. Our results thus provide empirical support for existing regulatory practice. Other important variables explaining bank failure dynamics are bank's size and profitability.

Control of dissipation in superconducting films by magnetic stray fields

Hybrid superconducting/magnetic nanostructures on Si substrates have been built with identical physical dimensions but different magnetic configurations. By constructing arrays based on Co-dots with in-plane, out-of-plane, and vortex state magnetic configurations, the stray fields are systematically tuned. Dissipation in the mixed state of superconductors can be decreased (increased) by several orders of magnitude by decreasing (increasing) the stray magnetic fields. Furthermore, ordering of the stray fields over the entire array helps to suppress dissipation and enhance commensurability effects increasing the number of dissipation minima.Comment: 16 pages including 4 figures; accepted in Applied Physics Letter

Effective penetration length and interstitial vortex pinning in superconducting films with regular arrays of defects

In order to compare magnetic and non-magnetic pinning we have nanostructured two superconducting films with regular arrays of pinning centers: Cu (non-magnetic) dots in one case, and Py (magnetic) dots in the other. For low applied magnetic fields, when all the vortices are pinned in the artificial inclusions, magnetic dots prove to be better pinning centers, as has been generally accepted. Unexpectedly, when the magnetic field is increased and interstitial vortices appear, the results are very different: we show how the stray field generated by the magnetic dots can produce an effective reduction of the penetration length. This results in strong consequences in the transport properties, which, depending on the dot separation, can lead to an enhancement or worsening of the transport characteristics. Therefore, the election of the magnetic or non-magnetic character of the pinning sites for an effective reduction of dissipation will depend on the range of the applied magnetic field.Comment: 10 pages, 3 figure

Superconducting/magnetic three state nanodevice for memory and reading applications

We present a simple nanodevice that can operate in two modes: i) three-state memory and ii) reading device. The nanodevice is fabricated with an array of ordered triangular-shaped nanomagnets embedded in a superconducting thin film. The input signal is ac current and the output signal is dc voltage. Vortex ratchet effect in combination with out of plane magnetic anisotropy of the nanomagnets is the background physics which governs the nanodevice performance.Comment: 10 pages, 4 figure

Bank Market Power and Firm Finance: Evidence from Bank and Loan Level Data

We present new measures of market power for the banking industry in Colombia and estimate their effect on the cost of credit for non-financial firms. Our results suggest that bank competition increased during the 2006-2008 period even as concentration increased but decreased thereafter. Using a unique combination of loan, firm and bank-level data sets we are also able to show that banks loosing overall market power –measured by the average price-cost margin– decrease interest rates to small firms, but increase rates to firms with which they have the oldest credit relationships. This suggests (i) the existence of market power that is specific to the bank-firm re lationship (i .e., informa-tional lock-in and hold-up problems due to switching costs), and (ii) that size may be capturing other firm attributes such as observable risk, scale effects or implicit collateral

A value for directed communication situations

In this paper we introduce an extension of the model of restricted communication in cooperative games as introduced in Myerson (1977) by allowing communication links to be directed and the worth of a coalition to depend on the order in which the players enter the coalition. Therefore, we model the communication network by a directed graph and the cooperative game by a generalized characteristic function as introduced in Nowak and Radzik (1994). We generalize the Myerson value for undirected (or standard) communication situations to the context of directed communication and provide two axiomatizations of this digraph Myerson value using component efficiency and either fairness or the balanced contributions property