The Impact of Key Audit Matters (KAMs) Disclosure on Investor Reactions: Post-COVID-19 Evidence from Thailand

 

ผลกระทบของการเปิดเผยเรื่องสำคัญในการตรวจสอบต่อการตอบสนองของนักลงทุน : หลักฐานเชิงประจักษ์ภายหลังสถานการณ์โควิด-19 ของประเทศไทย

 

 

Received:
January 28, 2026

Revised:
April 16, 2026

Accepted:
May 1, 2026

Dr.Rojana Khunkaew

Assistant Professor of Department of Accountancy,

Faculty of Management Sciences, Prince of Songkla University

 

 

วันที่ได้รับต้นฉบับบทความ :
28 มกราคม 2569

วันที่แก้ไขปรับปรุงบทความ :
16 เมษายน 2569

วันที่ตอบรับตีพิมพ์บทความ :
1 พฤษภาคม 2569

ดร.รจนา ขุนแก้ว

ผู้ช่วยศาสตราจารย์ประจำสาขาวิชาการบัญชี

คณะวิทยาการจัดการ มหาวิทยาลัยสงขลานครินทร์

 

 

Keywords:

Key Audit Matters (KAMs),
Investor Reaction, Cumulative Abnormal Return (CAR),
SET Market, MAI Market,
Signaling Theory

ABSTRACT

This study examines the impact of Key Audit Matters (KAMs) disclosures on investor reactions in the Stock Exchange of Thailand (SET) and the Market for Alternative Investment (MAI during 2021–2023, with investor reactions measured by Cumulative Abnormal Return (CAR).  The results show that SET-listed companies disclose a greater number of KAM issues and provide longer KAM descriptions than MAI firms.  Panel data analysis using a random effects model indicates that the number of KAM issues has a significant negative effect on investor reactions in both markets, suggesting that investors interpret a higher number of issues as a signal of increased risk. In contrast, the word count of KAM disclosures is positively associated with investor reactions in the SET, while in the MAI market, the word count of KAM disclosures does not significantly.  Considering the timing of investor responses differs between markets. Investors in the SET react within a two-day window, whereas those in the MAI respond within approximately six days. Consistent with the Efficient Market Hypothesis, these findings indicate that the SET incorporates public information into stock prices more rapidly than the MAI, implying relatively higher market efficiency. However, neither market fully satisfies semi-strong form efficiency.

 

 

คำสำคัญ :

เรื่องสำคัญในการตรวจสอบ
การตอบสนองของนักลงทุน ผลตอบแทนผิดปกติสะสม
ตลาดหลักทรัพย์แห่งประเทศไทย
ตลาดหลักทรัพย์เอ็ม เอ ไอ
ทฤษฎีการส่งสัญญาณ

บทคัดย่อ

การศึกษาครั้งนี้วิเคราะห์ผลกระทบของการเปิดเผยเรื่องสำคัญในการตรวจสอบต่อการตอบสนองของนักลงทุนของบริษัทจดทะเบียนในตลาดหลักทรัพย์แห่งประเทศไทย และตลาดหลักทรัพย์เอ็ม เอ ไอ ในช่วงปี ค.ศ. 2021–2023 โดยวัดการตอบสนองของนักลงทุนด้วยผลตอบแทนผิดปกติสะสม ผลการศึกษาพบว่า บริษัทในตลาดหลักทรัพย์แห่งประเทศไทยมีการเปิดเผยจำนวนประเด็นและจำนวนคำของเรื่องสำคัญในการตรวจสอบมากกว่าบริษัทในตลาดหลักทรัพย์เอ็ม เอ ไอ การวิเคราะห์ข้อมูลแบบพาเนลด้วยแบบจำลองผลสุ่ม พบว่า จำนวนประเด็นของเรื่องสำคัญในการตรวจสอบมีผลกระทบเชิงลบอย่างมีนัยสำคัญต่อการตอบสนองของนักลงทุนในทั้งสองตลาด สะท้อนว่า นักลงทุนตีความจำนวนประเด็นที่เพิ่มขึ้นเป็นสัญญาณของความเสี่ยง ในทางตรงกันข้ามจำนวนคำของเรื่องสำคัญมีความสัมพันธ์เชิงบวกกับการตอบสนองของนักลงทุนในตลาดหลักทรัพย์แห่งประเทศไทย ขณะที่ในตลาดหลักทรัพย์เอ็ม เอ ไอ ไม่พบผลกระทบอย่างมีนัยสำคัญ นอกจากนี้นักลงทุนในตลาดหลักทรัพย์แห่งประเทศไทยตอบสนองต่อข้อมูลภายใน 2 วัน ขณะที่ตลาดหลักทรัพย์เอ็ม เอ ไอ ใช้เวลาประมาณ 6 วัน ซึ่งสอดคล้องกับแนวคิดตลาดหลักทรัพย์ที่มีประสิทธิภาพ ที่ชี้ว่า ตลาดหลักทรัพย์แห่งประเทศไทยสะท้อนข้อมูลเข้าสู่ราคาหุ้นได้รวดเร็วกว่าจึงมีระดับประสิทธิภาพของตลาดสูงกว่า อย่างไรก็ตาม ทั้งสองตลาดยังไม่สามารถจัดว่า เป็นตลาดที่มีประสิทธิภาพระดับกลางอย่างสมบูรณ์

 

 

 

HOW TO CITE

 

Khunkaew, R. (2026). The Impact of key audit matters (KAMs) disclosure on investor reactions: Post-COVID-19 evidence from Thailand. Journal of Accounting Profession, 22(75), 75-105. https://doi.org/10.14456/jap.2026.13

 

 

 

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