本研究探討泰國股票市場如何對企業永續揭露進行定價。以2020年至2024年間61家SET100高排放上市公司為研究對象，本研究提出「信譽悖論」框架，主張在泰國自願揭露環境下，投資者重視資訊可信度，而非碳排放表現本身。 研究發現，碳排放強度與企業價值無顯著關聯，ESG聲譽則與正向市場溢價相關。第三方碳核查雖帶來實際成本，卻未能轉化為相應的市場估值效益，顯示信譽投資先於市場認可。ESG溢價具有條件性，取決於財務背景：僅存在於低股息收益率企業，在高股息收益率企業中消失，支持信號替代機制的存在。 上述發現豐富了新興市場碳定價文獻，並對泰國永續揭露政策與排放交易制度設計具有直接參考價值。;This study examines how Thai equity markets price corporate sustainability disclosures. Using a panel of 61 high-emission SET100-listed firms over 2020–2024， we develop the Credibility Paradox framework， arguing that investors reward disclosure credibility rather than underlying carbon performance in Thailand′s voluntary disclosure environment. We find that carbon emissions intensity shows no association with firm value， while ESG reputation commands a meaningful market premium. Third-party verification imposes real accounting costs without generating a corresponding valuation benefit， suggesting that credibility investments precede market recognition. The ESG premium is conditional on financial context: it exists only among firms with low dividend yields and disappears where strong financial signals already reduce investor uncertainty， consistent with a signal substitutability mechanism. These findings contribute to the literature on carbon pricing in emerging markets and carry direct implications for Thailand′s sustainability disclosure policy and anticipated Emissions Trading Scheme.
