Event studies: A methodology review

Originally developed as a statistical tool for empirical research in accounting and finance, event studies have since migrated to other disciplines as well, including economics, history, law, management, marketing, and political science. Despite the elegant simplicity of a standard event study, variations in methodology and their relative merits continue to attract attention in the literature. This paper reviews some of the fundamental topics in short‐term event study methodology, with an attempt to add new perspectives to some pressing topics.     

“十二五”时期区域经济、社会进一步协调发展的三段式构想

在＂十一五＂时期经济、社会发展的基础上,＂十二五＂时期区域经济、社会的进一步协调发展,应尊重客观经济规律、区域特点和低碳环保的要求,分三个阶段,有步骤、分层次地将＂四大板块＂和＂类型区＂中的经济社会资源进行挖掘、整合、调整,以达到总体综合实力的提高。     

Short-sale constraints and price bubbles

Miller (1977) demonstrated that if investors have heterogeneous beliefs and short sales are restricted, trade of a security will disproportionately reflect positive information, generating a price bubble. As this intuition applies most relevantly to short intervals of trade, a question arises as to the longevity of such a bubble. In this paper, I argue that a bubble effected by short-sale constraints persists only if agents cannot distinguish between order flow caused by positive information or order flow caused by the constraints. If the constraint is common knowledge, it should have no effect on the long-term pricing of the stock. If, however, the constraint is random and unknown, a price bubble may form.     

Wars and Child Health: Evidence from the Eritrean-Ethiopian Conflict

Conflict between and within countries can have lasting health and economic consequences, but identifying such effects can be empirically challenging. This paper uses household survey data from Eritrea to estimate the effect of exposure to the 1998-2000 Eritrea-Ethiopia war on children's health. The identification strategy exploits exogenous variation in the conflict's geographic extent and timing and the exposure of different birth cohorts to the fighting. The unique survey data include details on each household's migration history, which allows us to measure a child's geographic location during the war and without which war exposure would be incorrectly classified. War-exposed children have lower height-for-age Z-scores, with similar effects for children born before or during the war. Both boys and girls who are born during the war experience negative impacts due to conflict. Effects are robust to including region-specific time trends, alternative conflict exposure measures, and mother fixed effects.     

REGIONAL VARIATION IN LIVELIHOOD STRATEGIES IN MALAWI

We identified livelihood strategies at the household level as a function of assets held using survey data from Malawi. We only included endowments that we expected to be predetermined. As expected, land, household size, age and primary education are important determinants of livelihood strategies. It also turned out to be significant regional variation in livelihood strategies, with more diversification in the southern region, and with regional variation in the role of ethnic and religious identity as determinants of livelihood strategies. In particular, we found that households from the Chewa community have more livelihood opportunities in the south, where they are in a minority.     

Short Selling: The Impact of SEC Rule 201 of 2010

Despite its sizeable compliance costs, we are unable to document any clear benefits of SEC Rule 201 in ensuring fair valuations and price stability, promoting higher liquidity and execution quality, or preventing a sudden flash crash or prolonged market crises. Our daily and intraday analysis of data both before and after Rule 201 finds that short sellers are naturally more active before the occurrence of negative returns, not after significant price declines. Our simulation results show that Rule 201 further curtails short selling during normal periods, but is not binding on short sellers during the volatile period of the 2008 financial crisis.     

Testing the growth effects of structural change

Against the backdrop of Baumol's model of ‘unbalanced growth’, a recent strand of literature has presented models that manage to reconcile structural change with Kaldor's ‘stylized fact’ of the relative constancy of per-capita real GDP growth. Another strand of literature goes beyond this, arguing that the expenditure shifts toward Baumol's ‘stagnant’ sector stimulate rather than dampen long-term economic growth because of the human capital-accumulating nature of major ‘stagnant’ services (like health care and education). This paper tests the relationship between structural change and economic growth empirically by means of a Granger-causality analysis of a panel of 18 OECD countries.     

THE TIMING OF UPGRADES*

By using a durable‐goods monopolist model, this paper investigates the timing of upgrades. I consider a three‐period model where the monopolist can upgrade the product in the second and third periods by investing in R&D. I analyse the non‐commitment and commitment cases. In the latter case, the decision on the timing of upgrades is made in the first period in advance. It is shown that the time‐inconsistency problem causes the monopolist in the non‐commitment case to release a new version more rapidly than in the commitment case. Moreover, even in the non‐commitment case, the release of a new version can still be later than the optimum from the social viewpoint.     

Renegotiation of cash flow rights in the sale of VC-backed firms

Incomplete contracting theory suggests that venture capitalist (VC) cash flow rights, including liquidation preferences, could be subject to renegotiation. Using a hand-collected data set of sales of Silicon Valley firms, we find common shareholders do sometimes receive payment before VCs’ liquidation preferences are satisfied. However, such deviations from VCs' cash flow rights tend to be small. We also find that renegotiation is more likely when governance arrangements, including the firm's choice of corporate law, give common shareholders more power to impede the sale. Our study provides support for incomplete contracting theory, improves understanding of VC exits, and suggests that choice of corporate law matters in private firms.