Climate litigation has become a material governance mechanism that can affect strategy, disclosure, and long-horizon planning. This article examines whether equity markets price climate litigation as value-relevant information for publicly listed defendants. We assemble a cross-regional sample of corporate climate lawsuits against listed North American and European firms over 2005–2021 using the Sabin Center climate litigation databases (with contributions from the London School of Economics), yielding 279 filing firm-events and 78 decision firm-events. Using a standard event-study design, we estimate cumulative average abnormal returns around litigation filings and judicial decisions. The estimates indicate a negative market response at filing (a 3-day cumulative average abnormal return of \(-0.35%\)) and a larger negative response after unfavourable decisions (\(-0.99%\)). Effects are stronger among “Carbon Major” defendants and for novel or first-in-jurisdiction filings, although narrower subsample results are interpreted cautiously. Taken together, the evidence supports climate litigation as a managerial and planning-relevant risk channel with implications for enterprise risk management, transition planning, governance, and investor communication.