DNA methylation age has been used in recent studies as an epigenetic marker of accelerated cellular aging, whose contribution to the brain structural changes was lately acknowledged. We aimed to ...characterize the association of epigenetic age (i.e. estimated DNA methylation age) and its acceleration with surface area, cortical thickness, and volume in healthy young adults. Using the multi-tissue method (Horvath S. DNA methylation age of human tissues and cell types. 2013. Genome Biol 14), epigenetic age was computed with saliva sample. Epigenetic age acceleration was derived from residuals after adjusting epigenetic age for chronological age. Multiple regression models were computed for 148 brain regions for surface area, cortical thickness, and volume using epigenetic age or accelerated epigenetic age as a predictor and controlling for sex. Epigenetic age was associated with surface area reduction of the left insula. It was also associated with cortical thinning and volume reduction in multiple regions, with prominent changes of cortical thickness in the left temporal regions and of volume in the bilateral orbital gyri. Finally, accelerated epigenetic age was negatively associated with right cuneus gyrus volume. Our findings suggest that understanding the mechanisms of epigenetic age acceleration in young individuals may yield valuable insights into the relationship between epigenetic aging and the cortical change and on the early development of neurocognitive pathology among young adults.
This study investigates the impacts of the introductions of commodity exchange-traded notes on the corresponding underlying commodity futures markets around their issuance announcement and listing ...dates. Focusing on the Korean market, a leading and influential emerging market, we adopt an event study approach to analyze changes in futures returns and volatilities. Considering the potential cyclicality and seasonality of commodity futures dynamics, we use the Hodrick-Prescott filter to decompose the return processes into four separate components, that is, the trend, seasonal, cyclical, and irrational components, and we analyze only the irrational component as the abnormal excess return. We observe significant but temporary abnormal returns before issuance announcements, implying a hedging effect; significant negative abnormal returns after announcements of inverse products, indicating a short-sale constraint removal effect; and significant positive returns on the announcement dates of leveraged product portfolios, indicating a signaling effect. We also find that the volatility of the seasonal component significantly decreases after the introductions of leveraged products.
This study reexamines the influence of different investor types' net options demand on the KOSPI200 options-implied volatility dynamics. We extend Bollen and Whaley (2004) by accounting for options ...traders' hedging demand for futures contracts, intraday seasonality, dynamic impacts of net buying pressure on implied volatility, and the effect of regulatory reform in the options market. Our empirical analyses provide evidence for the direction-learning behavior of foreign institutional investors. We further show that foreign institutions’ net demand is the most informative about the underlying market volatility independent of the market reform, while domestic retail investors become partially informed only after the reform.
We use a high‐quality microstructure data set of KOSPI 200 index options to examine the patterns of informed options trading around holidays, depending on options market characteristics. The ...information content of options trading increases around holidays, and this holiday effect is pronounced for out‐of‐the‐money calls and at‐the‐money puts. Informed large trades reinforce the holiday effects for out‐of‐the‐money call options. Foreign investors are generally informed, and their out‐of‐the‐money options trades are even more informed after holidays. Although domestic investors are less informed than their foreign competitors, their options trades seem to convey information both before and after holidays.
We examine the effect of funding liquidity changes on futures market liquidity, depending on economic sentiment. Futures market liquidity improves following negative funding liquidity shocks, and ...economic sentiment is an important determinant explaining this relationship. While individuals' trading is most significantly affected by sentiment, its response to funding liquidity shocks remains independent of sentiment effects. Domestic institutions' reactions depend on the sentiment regime; they trade futures contracts more actively as funding liquidity becomes more abundant (scarcer) when sentiment is more pessimistic (optimistic). Foreigners, following negative funding liquidity shocks, generally increase their futures trading, whereas their trading decreases under the extremely pessimistic sentiment. Domestic banks and pension funds provide liquidity to the futures market even when sentiment is pessimistic.
Over 10,000 South Korean nurses were sent to West Germany in the 11-year period between 1965 and 1976. It is known that they were dispatched because of South Korea’s need for capital and expertise ...after the Korean War (1950–1953). To assist in this endeavor, West Germany helped South Korea through development support (educational aid). However, Korean nurses were not simply trainees since they had received a proper education and qualifications. Thus, this “educational aid” could critically be termed little more than “labor trade” because the highly educated nurses were forced to take work with lower wages than their background warranted.
This study reexamines the determinants of insurance firms' hybrid bond issuances. We also analyze the effects of these issuances on their issuers' financial solvency and performance. Logistic ...regression reveals that the likelihood of issuing a hybrid bond increases when the risk-based capital ratio is lower and when net income is greater. Additionally, difference-in-differences estimations with fixed effects show that hybrid bond issuances enhance insurance firms' insolvency risk and liquidity ratio but do not significantly improve overall financial solvency indices. The insolvency risk is mitigated when the bonds are issued to foreign creditors.
•We examine insurance firms' hybrid bond issuance behaviors.•Insurance firms with poor financial statuses are more likely to issue hybrid bonds.•Hybrid bond issuances do not significantly improve issuers' financial soundness.
•Subordinated debt issuances nonlinearly deteriorate bank performance.•Subordinated debt issuances decrease (increase) the bank profitability (insolvency risk).•Redemptions of subordinated debt have ...no significant impact on bank performance.
We investigate whether changes in subordinated debt have a nonlinear effect on bank performance. Subordinated debt changes negatively affect bank performance, both linearly and quadratically. Increases in subordinated debt, namely, issuances, deteriorate (increase) bank profitability (insolvency risk), while the effects of the debt decreases, namely, redemptions, are insignificant.
This study examines the effectiveness of the Basel III capital framework for mitigating procyclical behavior in the banking sector regarding macroeconomic variability and uncertainty. Our sample ...includes Korean banking industry data from 2001 to 2018. Using fixed- and random-effects panel data and fixed-effects difference-in-differences approaches, we discover that procyclicality in banks’ performance and capital factors is mitigated after the Basel III accord is adopted. The capital adequacy ratio’s volatility increases, whereas the loans-to-assets ratio increases and stabilizes. The Basel III accord therefore effectively serves its intended purpose, as it encourages banks to serve as shock absorbers for the economy and reduces economic uncertainty.
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•Analyst recommendation revisions impact stock returns, trading behavior, and investor sentiment.•Sentiment explains overconfidence when investors’ prior beliefs are overly optimistic ...or pessimistic.•Domestic investors drive irrational sentiment trades around analyst recommendation revisions.
This study examines irrational stock market reactions to analyst recommendation revisions depending on investor sentiment levels prior to analyst report announcements. We construct a firm-specific sentiment indicator by extending Huang et al. (2015, Review of Financial Studies, 28, pp.791–837). Analyst recommendation revisions have more pronounced effects for downgrades, which is attributable to sentiment effects. Domestic investors tend to react less to upgrades (downgrades) news when their prior beliefs are pessimistic (optimistic), implying that they are overconfident. The domestic investors drive sentiment trades, whereas foreign investors are not biased.
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