Chulalongkorn University Theses and Dissertations (Chula ETD)

Other Title (Parallel Title in Other Language of ETD)

การกระจายความเสี่ยงทางธุรกิจและความเสี่ยงหุ้นสามัญในประเทศไทย หลักฐานจากผลกระทบเศรษฐกิจโลกหยุดชะงัก

Year (A.D.)


Document Type

Independent Study

First Advisor

Suparatana Tanthanongsakkun


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





The objective of this paper is to investigate the impact of corporate diversification on stock risk for 345 companies listed on Stock Exchange of Thailand during the sample period from 4 January 2017 to 30 December 2021 which covers both Covid and pre-Covid period. Furthermore, the differences in effect between Covid and pre-Covid period are also studied. The result shows that diversifying through only business segments and ignoring global diversification increases stock volatility. Furthermore, it also shows that diversifying through only business segments and ignoring global diversification increases stock volatility during the Covid period compared to pre-Covid period. The result is consistent with findings of Onali and Mascia (2022) who study US companies. However, there is no significant relationship found between only global diversification and stock volatility during the whole sample period as well as the Covid period. The ability of companies in alleviating the impact of such global shocks that could affect different geographical regions in different time periods might be if they depend only on business segment diversification. The profitability of the companies also affected the most if they only consider diversifying through business segment during pandemic. Similar to the case of US, the coinsurance effect of diversifying by business segments might not benefit investors in Thailand, as it might be done quite easily by investing in stocks of firms operate in different industries.



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