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Updates every hour. Last Updated: 29-Oct-2025 08:11 ET (29-Oct-2025 12:11 GMT/UTC)
Spotting a concussion can be tricky. After a potential head injury, you can ask if the person feels dizzy or has a headache — but that relies on self-reporting, which isn’t always accurate.
What if there were a way to take the guesswork out of it?
That’s the problem Trent Guess, an associate professor at the University of Missouri College of Health Sciences, and Jacob Thomas, a Mizzou doctoral student, have set out to solve.
This study examines the short- and long-term stock performance of small- and medium-sized enterprises (SMEs) following the issuance of hybrid securities—including bonds with warrants, convertible bonds, and exchangeable bonds—in the KOSDAQ market from 2016 to 2020. Using a sample of 204 issuers, we employ event study methodology and buy-and-hold abnormal returns to evaluate stock performance around the announcement date and over extended periods. Our findings indicate significantly positive cumulative abnormal returns in the short run, suggesting investor optimism. However, long-run analysis reveals substantial underperformance, particularly for bonds with warrants and exchangeable bonds, with significant declines over two- and three-year horizons. These results imply that managers may exploit overvaluations in hybrid securities markets, leading to long-term underperformance. Firm-specific factors such as growth opportunities, financial investor involvement, and corporate governance also influence performance. This study contributes to the literature by focusing on an emerging market context and incorporating exchangeable bonds, offering novel insights for investors and policymakers in emerging economies.
Women, non-native English speakers and those from lower-income countries published fewer English-language peer-reviewed papers than men, native English speakers and those from higher-income countries, according to a study published September 18th in the open-access journal PLOS Biology by Tatsuya Amano from The University of Queensland, Australia, and colleagues.
For decades, financial risk has been measured with Gaussian-based models built on the assumption that markets follow a bell-shaped curve. These models underpin decisions from investment strategies to regulation, yet they fail to capture the true scale of market disruptions. A new doctoral dissertation from the University of Vaasa, Finland, argues that power laws offer a more accurate lens through which to understand financial markets’ risk dynamics.