A Cost-Benefit Analysis of the New Orleans Flood Protection System

In the early stages of rebuilding New Orleans, a decision has to be made on the level of flood protection the city should implement. Such decisions are usually based on cost-benefit analyses. But in such an analysis, the results are contingent on a number of underlying assumptions and varying these assumptions can lead to different recommendations. Indeed, though a standard first-order analysis rules out category 5 hurricane protection, taking into account climate change and other human-related disruptions of environment, second-order impacts of large-scale disasters, possible changes in the discount rate, risk aversion and damage heterogeneity may make such a hurricane protection a rational investment, even if countervailing risks and moral hazard issues are included in the analysis. These results stress the high sensitivity of the CBA recommendation to several uncertain assumptions, highlight the importance of second-order costs and damage heterogeneity in welfare losses, and show how climate change creates an additional layer of uncertainty in infrastructure design that increases the probability of either under-adaptation (and increased risk) or over-adaptation (and sunk costs).Cost-Benefit analysis; Hurricane risk; New Orleans; Climate change

A Cost-Benefit Analysis of the New Orleans Flood Protection System

In the early stages of rebuilding New Orleans, a decision has to be made on the level of flood protection the city should implement. Such decisions are usually based on cost-benefit analyses. But in such an analysis, the results are contingent on a number of underlying assumptions and varying these assumptions can lead to different recommendations. Indeed, though a standard first-order analysis rules out category 5 hurricane protection, taking into account climate change and other human-related disruptions of environment, second-order impacts of large-scale disasters, possible changes in the discount rate, risk aversion and damage heterogeneity may make such a hurricane protection a rational investment, even if countervailing risks and moral hazard issues are included in the analysis. These results stress the high sensitivity of the CBA recommendation to several uncertain assumptions, highlight the importance ofsecond-order costs and damage heterogeneity in welfare losses, and show how climate change creates an additional layer of uncertainty in infrastructure design that increases the probability of either under-adaptation (and increased risk) or over-adaptation (and sunk costs).

A Cost-Benefit Analysis of the New Orleans Flood Protection System

International audienceIn the early stages of rebuilding New Orleans, a decision has to be made on the level of flood protection the city should implement. Such decisions are usually based on cost-benefit analyses. But in such an analysis, the results are contingent on a number of underlying assumptions and varying these assumptions can lead to different recommendations. Indeed, though a standard first-order analysis rules out category 5 hurricane protection, taking into account climate change and other human-related disruptions of environment, second-order impacts of large-scale disasters, possible changes in the discount rate, risk aversion and damage heterogeneity may make such a hurricane protection a rational investment, even if countervailing risks and moral hazard issues are included in the analysis. These results stress the high sensitivity of the CBA recommendation to several uncertain assumptions, highlight the importance of second-order costs and damage heterogeneity in welfare losses, and show how climate change creates an additional layer of uncertainty in infrastructure design that increases the probability of either under-adaptation (and increased risk) or over-adaptation (and sunk costs)

Optimal market making

Market makers provide liquidity to other market participants: they propose prices at which they stand ready to buy and sell a wide variety of assets. They face a complex optimization problem with both static and dynamic components. They need indeed to propose bid and offer/ask prices in an optimal way for making money out of the difference between these two prices (their bid-ask spread). Since they seldom buy and sell simultaneously, and therefore hold long and/or short inventories, they also need to mitigate the risk associated with price changes, and subsequently skew their quotes dynamically. In this paper, (i) we propose a general modeling framework which generalizes (and reconciles) the various modeling approaches proposed in the literature since the publication of the seminal paper "High-frequency trading in a limit order book" by Avellaneda and Stoikov, (ii) we prove new general results on the existence and the characterization of optimal market making strategies, (iii) we obtain new closed-form approximations for the optimal quotes, (iv) we extend the modeling framework to the case of multi-asset market making and we obtain general closed-form approximations for the optimal quotes of a multi-asset market maker, and (v) we show how the model can be used in practice in the specific (and original) case of two credit indices

The ₉₅RGD₉₇ sequence on the A alpha chain of fibrinogen is essential for binding to its erythrocyte receptor

Background: Erythrocyte aggregation, a cardiovascular risk factor, is increased by high plasma fibrinogen levels. Here, the effect of different fibrinogen mutations on binding to its human erythrocyte receptor was assessed in order to identify the interaction sites. Methods: Three fibrinogen variants were tested, specifically mutated in their putative integrin recognition sites on the Aα chain (mutants D97E, D574E and D97E/D574E) and compared with wild-type fibrinogen. Results: Atomic force microscopy-based force spectroscopy measurements showed a significant decrease both on the fibrinogen–erythrocyte binding force and on its frequency for fibrinogen with the D97E mutation, indicating that the corresponding arginine–glycine–aspartate sequence (residues 95–97) is involved in this interaction, and supporting that the fibrinogen receptor on erythrocytes has a β3 subunit. Changes in the fibrin clot network structure obtained with the D97E mutant were observed by scanning electron microscopy. Conclusion: These findings may lead to innovative perspectives on the development of new therapeutic approaches to overcome the risks of fibrinogen-driven erythrocyte hyperaggregation

Stochastic Models of Limit Order Markets

During the last two decades most stock and derivatives exchanges in the world transitioned to electronic trading in limit order books, creating a need for a new set of quantitative models to describe these order-driven markets. This dissertation offers a collection of models that provide insight into the structure of modern financial markets, and can help to optimize trading decisions in practical applications. In the first part of the thesis we study the dynamics of prices, order flows and liquidity in limit order markets over short timescales. We propose a stylized order book model that predicts a particularly simple linear relation between price changes and order flow imbalance, defined as a difference between net changes in supply and demand. The slope in this linear relation, called a price impact coefficient, is inversely proportional in our model to market depth - a measure of liquidity. Our empirical results confirm both of these predictions. The linear relation between order flow imbalance and price changes holds for time intervals between 50 milliseconds and 5 minutes. The inverse relation between the price impact coefficient and market depth holds on longer timescales. These findings shed a new light on intraday variations in market volatility. According to our model volatility fluctuates due to changes in market depth or in order flow variance. Previous studies also found a positive correlation between volatility and trading volume, but in order-driven markets prices are determined by the limit order book activity, so the association between trading volume and volatility is unclear. We show how a spurious correlation between these variables can indeed emerge in our linear model due to time aggregation of high-frequency data. Finally, we observe short-term positive autocorrelation in order flow imbalance and discuss an application of this variable as a measure of adverse selection in limit order executions. Our results suggest that monitoring recent order flow can improve the quality of order executions in practice. In the second part of the thesis we study the problem of optimal order placement in a fragmented limit order market. To execute a trade, market participants can submit limit orders or market orders across various exchanges where a stock is traded. In practice these decisions are influenced by sizes of order queues and by statistical properties of order flows in each limit order book, and also by rebates that exchanges pay for limit order submissions. We present a realistic model of limit order executions and formalize the search for an optimal order placement policy as a convex optimization problem. Based on this formulation we study how various factors determine investor's order placement decisions. In a case when a single exchange is used for order execution, we derive an explicit formula for the optimal limit and market order quantities. Our solution shows that the optimal split between market and limit orders largely depends on one's tolerance to execution risk. Market orders help to alleviate this risk because they execute with certainty. Correspondingly, we find that an optimal order allocation shifts to these more expensive orders when the execution risk is of primary concern, for example when the intended trade quantity is large or when it is costly to catch up on the quantity after limit order execution fails. We also characterize the optimal solution in the general case of simultaneous order placement on multiple exchanges, and show that it sets execution shortfall probabilities to specific threshold values computed with model parameters. Finally, we propose a non-parametric stochastic algorithm that computes an optimal solution by resampling historical data and does not require specifying order flow distributions. A numerical implementation of this algorithm is used to study the sensitivity of an optimal solution to changes in model parameters. Our numerical results show that order placement optimization can bring a substantial reduction in trading costs, especially for small orders and in cases when order flows are relatively uncorrelated across trading venues. The order placement optimization framework developed in this thesis can also be used to quantify the costs and benefits of financial market fragmentation from the point of view of an individual investor. For instance, we find that a positive correlation between order flows, which is empirically observed in a fragmented U.S. equity market, increases the costs of trading. As the correlation increases it may become more expensive to trade in a fragmented market than it is in a consolidated market. In the third part of the thesis we analyze the dynamics of limit order queues at the best bid or ask of an exchange. These queues consist of orders submitted by a variety of market participants, yet existing order book models commonly assume that all orders have similar dynamics. In practice, some orders are submitted by trade execution algorithms in an attempt to buy or sell a certain quantity of assets under time constraints, and these orders are canceled if their realized waiting time exceeds a patience threshold. In contrast, high-frequency traders submit and cancel orders depending on the order book state and their orders are not driven by patience. The interaction between these two order types within a single FIFO queue leads bursts of order cancelations for small queues and anomalously long waiting times in large queues. We analyze a fluid model that describes the evolution of large order queues in liquid markets, taking into account the heterogeneity between order submission and cancelation strategies of different traders. Our results show that after a finite initial time interval, the queue reaches a specific structure where all orders from high-frequency traders stay in the queue until execution but most orders from execution algorithms exceed their patience thresholds and are canceled. This "order crowding" effect has been previously noted by participants in highly liquid stock and futures markets and was attributed to a large participation of high-frequency traders. In our model, their presence creates an additional workload, which increases queue waiting times for new orders. Our analysis of the fluid model leads to waiting time estimates that take into account the distribution of order types in a queue. These estimates are tested against a large dataset of realized limit order waiting times collected by a U.S. equity brokerage firm. The queue composition at a moment of order submission noticeably affects its waiting time and we find that assuming a single order type for all orders in the queue leads to unrealistic results. Estimates that assume instead a mix of heterogeneous orders in the queue are closer to empirical data. Our model for a limit order queue with heterogeneous order types also appears to be interesting from a methodological point of view. It introduces a new type of behavior in a queueing system where one class of jobs has state-dependent dynamics, while others are driven by patience. Although this model is motivated by the analysis of limit order books, it may find applications in studying other service systems with state-dependent abandonments

Buying hedonic and high involvement products in a multi-channel environment

Retailing has faced huge environmental changes due to the development of online channel, leading to a need to define the roles of sales channels in different situations. This thesis discusses how the characteristics of hedonic and high involvement products influence consumers’ purchase process in a multi-channel environment. The theoretical framework of this thesis consists theories on product type, multi-channel retailing and purchase process. Based on theories, buying a hedonic and high involvement product requires physical product evaluation and profound information search. The purchase process has two phases; search and purchase. The search is conducted in online channel due to the effectiveness and convenience, but the product is bought from offline channel in order to reduce the purchase risk. This is a qualitative study and consumer interviews were used as a method to data collection. The results of the empirical research revealed that product class has implications to purchase process and a new phase between search and purchase was identified. The purchase process of hedonic and high involvement products has therefore three phases; search, confirmation and purchase. Consumer needs to have a physical experience in order to evaluate the quality of a hedonic product, which is acquired often already in the search phase. The risk and importance attached to the purchase decision drives consumers to enhanced information search, which is done mostly in online channel. Hedonic and high involvement products requires profound search phase, as consumers are not willing to make compromises with product requirements. The search phase aims to find the perfect product and after adequate information gathered, consumer reaches the confirmation of the decision. It is important that consumer have had a chance to evaluate the product physically to reduce the purchase risk and to be convinced that product evokes right feelings. The confirmation of the decision is outcome of using the benefits of both channels, which supports the characteristics of the product. After this confirmation the channel choice criteria changes and consumer focuses to maximize the benefits. The purchase phase was found to be mostly price driven and consumer searches the cheapest channel to buy the product. Online channel was found to have an advantage in price competition, but offline channel was also used for purchasing because of it’s ability to provide immediate satisfaction and enjoyable purchase experience. Therefore, individual’s preferences can have a great impact on purchase process overcoming the channel utility and complicating the anticipation of the process

Banking market structure and bank intermediation strategies in emerging markets: three essays

This thesis focuses on bank market structure and the effect of changes to this structure on intermediation strategies using a dataset that covers many regions of the world. Employing different estimation techniques and methodologies, and using a novel approach to each line of research, this thesis provides the following robust results: first, increase banking competition weakens the effectiveness of monetary policy. This is because an increase in the degree of market power increases the response of bank lending to the monetary policy stance. Second, competition increases stability as banks diversify across and within their business activities. Third, the high net-interest margin and relatively low insolvency risk among banks in developing countries could be attributed to a high degree of market power and the use of internal capital financing. The thesis makes the following contributions to the literature: first, in order to gain new insights and provide new dimensions to the existing literature, each of the three core chapters employs an estimation strategy that is new in the literature and which offers more scope for investigation. For instance, the positive influence of revenue diversification on the competition-stability nexus is new in the literature. Second, this thesis is first in considering how various measures of market power and a variety of bank funding strategies impact on banks performance. Furthermore, considering the banking structure-risk-lending channel hypothesis in assessing banks’ response to monetary shocks is also new in the monetary policy transmission literature. In conclusion, this thesis gives rise to important public policy recommendations. First, the strong link between market imperfections and the effectiveness of monetary policy indicators requires regulation that can resolve and offset the adverse effects of further increases in the degree of bank market power on the effectiveness of monetary transmission. Second, given the results of the role of diversification on the competition-stability relationship, there is no evidence to support regulatory initiative that restricts banks diversification activities. The third and final recommendation is on the concept of market power: bank market power in itself is not detrimental to banking activities, but the level and the application of it could negatively affect bankinsolvency risk. Therefore, supervisory, regulatory and competition authorities should coordinate to put in place a comprehensive framework that allows banks to have a considerable amount of market power that is robust and consistent with any competition polic