Chulalongkorn University Theses and Dissertations (Chula ETD)

Other Title (Parallel Title in Other Language of ETD)

ผู้ขายชอร์ตมีข้อมูลเท่าเทียมกันหรือไม่ หลักฐานจากการประกาศอันดับความน่าเชื่อถือของประเทศสหรัฐอเมริกา

Year (A.D.)


Document Type

Independent Study

First Advisor

Tanakorn Likitapiwat


Faculty of Commerce and Accountancy (คณะพาณิชยศาสตร์และการบัญชี)

Department (if any)

Department of Banking and Finance (ภาควิชาการธนาคารและการเงิน)

Degree Name

Master of Science

Degree Level

Master's Degree

Degree Discipline





This study uses credit rating and daily short sale data of firms listed in NYSE from January 2015 to December 2021 to examine whether there is informed trading. Although post-announcement abnormal return is negatively correlated with abnormal short volume, no evidence of informed short selling is found. Higher level of pre-announcement abnormal short selling is positively correlated to default risk and also explained by the incentives of short sellers to short more when past returns are negative. Furthermore, increase in short selling that is preceded by credit watch placement is more pronounced before credit rating downgrades. Moreover, the evidence shows that cumulative abnormal return pre-announcement is positively and significantly correlated with the abnormal short sale activities pre-announcement. Lastly, this study provides evidence that institutional investors or medium or large trade size increase short position more heavily than smaller trade sizes.



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