This study examines the market reaction to voluntary Scope 3 disclosure of oil and gas producers. Using the mobility crisis due to the Covid-19 shutdown as the environment where oil and gas producers experienced a negative exogenous demand shock, we assess market reactions to Scope 3 and Use of Sold Products emission reporting of 48 oil and gas firms across 19 countries. We find that Scope 3 disclosure led to a negative market reaction and that the result is driven by downstream Use of Sold Products reporting. This study provides the first evidence on the elephant in the room for the global quest to achieve the Paris Agreement - the fossil fuel industry's product related emissions - and that investors react negatively to voluntary disclosure of Scope 3 emissions, especially the Use of Sold Products. This finding indicates that sustainability disclosure can be interpreted as a negative signal during the negative demand shock when the signal points out the size of risk exposures, which leads to an increase in equity risk premium for an industry that has no clear transition plan toward achieving net zero greenhouse gas emissions. Our findings indicate that institutional pressure – i.e. for firms headquartered in Europe - is the primary driver of voluntary Scope 3 disclosure, suggesting that such disclosures serve as a means for companies to preserve their legitimacy to operate.