In this study, we examine the wealth effects associated with the announcement of the Australian Carbon Pricing Scheme (the “carbon tax”), made by the then Prime Minster Julia Gillard on 24 February 2011. Building on studies that use the event study method originally developed by Fama et al. (1969) and Ball and Brown (1968), we propose a novel approach to analyzing announcements with unresolved uncertainty. With this approach, we separate out the news effect and the value effect associated with the announcement of the Australian Carbon Pricing Scheme. Our findings show that the average news effect associated with the announcement is 1.11% (A$254 million dollars), indicating that the market was favorably disposed towards the news that the government was taking action on climate change. The average value effect was −4.46% (−A$1.12 billion dollars), indicating that the scheme destroyed significant value for existing firms. The announcement of the Australian Carbon Pricing Scheme was more value-destructive for carbon-intensive firms (−6.97%) than for the other firms (−3.67%). The method presented in this study can be applied to any policy announcements with unresolved uncertainty.