Current accounting rules end regular amortization of goodwill and mandate annual tests for goodwill impairment and loss recognition, when appropriate. These rules make consideration of goodwill write-offs important and timely. In the study reported here, we found that the effects of goodwill write-off announcements were typically negative and material—on the order of −2.94 percent to −3.52 percent of the company's stock price. What makes goodwill write-off announcements especially noteworthy for investors is that additional effects of roughly −11.02 percent were realized by the end of a one-year post-announcement period. These results suggest that investors initially underreact to goodwill write-off announcements and that they need to be aware of the potential for further losses in the post-announcement period.