Economic sociology: a historical perspective

In this paper we briefly recall what is meant by economic sociology, basing our definition principally on the works of R. Swedberg and M. Cranovetter. We then focus on the questions and problematics which are more particularly relevant to the history of economic and sociological thought in such a way as to make explicit the kind of past in relation to which economic sociology is most pertinent. We shall thus be induced to correct certain explanations and to propose a slightly different perspective on the origin of economic sociology. This historical work enables us to formulate a definition of economic sociology based on two key concepts - economic institution and economic action - and allows us to articulate what economic sociology actually is, rather than merely describing what it is not. Finally, we show that these propositions are not without interest in relation to the present-day economic sociology that tends to go by the name - made fasionable by Granovetter and Swedberg - of ‘New Economic Sociology.’     

Do rating agencies’ decisions impact stock risks? Evidence from European markets

This article analyses the effect of rating agencies’ decisions on stock risks for European issuers concerning five kinds of events. Our approach is an extension of dummy variable regression event study methodology, using a GARCH(1,1) estimation to capture simultaneously the impact on both systematic and specific stock risks. This new methodology allows us to obtain both global results by categories of rating decisions and individual results, event by event. We document, globally, a positive impact of upgrading on systematic risk, a negative impact of rating confirmation on specific risk, and no significant impact in all other cases. Regarding event-by-event results, the proportion of rating actions exhibiting a significant effect on risk is almost always observed between 20% and 30%. The weak evidence of a global effect on systematic risk may be due to the lack of informational content of the rating decisions on the stocks’ risk, or the existence of rebalancing effects between systematic and idiosyncratic risks. Furthermore, it should be noticed that the decline in volatility in case of a rating affirmed is an insight of the certification role played by the agencies.     

A High‐Frequency Investigation of the Interaction between Volatility and DAX Returns

One of the most noticeable stylised facts in finance is that stock index returns are negatively correlated with changes in volatility. The economic rationale for the effect is still controversial. The competing explanations have different implications for the origin of the relationship: Are volatility changes induced by index movements, or inversely, does volatility drive index returns? To differentiate between the alternative hypotheses, we analyse the lead‐lag relationship of option implied volatility and index return in Germany based on Granger causality tests and impulse‐response functions. Our dataset consists of all transactions in DAX options and futures over the time period from 1995 to 2005. Analyzing returns over 5‐minute intervals, we find that the relationship is return‐driven in the sense that index returns Granger cause volatility changes. This causal relationship is statistically and economically significant and can be clearly separated from the contemporaneous correlation. The largest part of the implied volatility response occurs immediately, but we also observe a smaller retarded reaction for up to one hour. A volatility feedback effect is not discernible. If it exists, the stock market appears to correctly anticipate its importance for index returns.     

Food policy research for improving the reform of agricultural input and output markets in Central Asia

Agriculture is a significant component of the Central Asian economies. Since independence, the republics have implemented agricultural reforms in varying measure, yet production has fallen sharply across the region. The more ambitious agricultural reform programs have included measures aimed at liberalizing agricultural marketing, trade and prices. However, so far the expected supply response has yet to emerge. The objective of this paper is to highlight key policy and research issues surrounding reform of agricultural markets. It summarizes the main features of agricultural performance since the reforms, highlighting trends in grain and cotton, livestock, input use, and trade and analyzes key constraints to improvement of the sector, emphasizing price policy, sequencing problems, and institutional weakness. It presents a research agenda by identifying the main research needs for better agricultural policy design. It calls for more research on input and output market efficiency, private sector development, the effects of reform on farmers, sequencing issues, comparative advantage, water management, land tenure and farm size.     

Risk management lessons from Long‐Term Capital Management

The 1998 failure of Long‐Term Capital Management (LTCM) is said to have nearly blown up the world's financial system. For such a near‐catastrophic event, the finance profession has precious little information to draw from. By piecing together publicly available information, this paper draws risk management lessons from LTCM. LTCM's strategies are analysed in terms of the fund's Value at Risk (VAR) and the amount of capital necessary to support its risk profile. The paper shows that LTCM had severely underestimated its risk due to its reliance on short‐term history and risk concentration. LTCM also provides a good example of risk management taken to the extreme. Using the same covariance matrix to measure risk and to optimize positions inevitably leads to biases in the measurement of risk. This approach also induces the strategy to take positions that appear to generate 'arbitrage' profits based on recent history but also represent bets on extreme events, like selling options. Overall, LTCM's strategy exploited the intrinsic weaknesses of its risk management system.     

Mixed bundling auctions

We study multi-object auctions where agents have private and additive valuations for heterogeneous objects. We focus on the revenue properties of a class of dominant strategy mechanisms where a weight is assigned to each partition of objects. The weights influence the probability with which partitions are chosen in the mechanism. This class contains efficient auctions, pure bundling auctions, mixed bundling auctions, auctions with reserve prices and auctions with pre-packaged bundles. For any number of objects and bidders, both the pure bundling auction and separate, efficient auctions for the single objects are revenue-inferior to an auction that involves mixed bundling.     

Competition and productivity growth in South Africa

This article shows that mark‐ups are significantly higher in South African manufacturing industries than they are in corresponding industries worldwide. We test for the consequences of this low‐level of product market competition on productivity growth. The results of the paper are that high mark‐ups have a large negative impact on productivity growth in South African manufacturing industry. Our results are robust to three different data sources, two alternative measures of productivity growth, and three distinct measures of the mark‐up. Controlling for potential endogeneity of regressors does not eliminate the findings.     

Productivity, terms of trade and the ‘home market effect’

This paper analyzes the international transmission and welfare implications of productivity gains and changes in market size when macroeconomic adjustment occurs both along the intensive margin of trade (changes in the relative price of existing varieties of tradable goods) and the extensive margin (creation and destruction of varieties). We draw a distinction between productivity gains that enhance manufacturing efficiency and gains that lower the cost of firms' entry and of product differentiation. Countries with lower manufacturing costs have higher GDP but supply their products at lower international prices. Instead, countries with lower entry costs supply a larger array of goods at improved terms of trade. Output growth driven by demographic expansions, as well as government spending, is associated with an improvement in international relative prices and firms' entry. While trade liberalization may result in a smaller array of goods available to consumers, efficiency gains from deeper economic integration benefit consumers via lower goods prices. The international transmission mechanism and the welfare spillovers vary under different asset market structures, depending on trade costs, the elasticity of labor supply, and consumers' taste for varieties.