This paper examines short-sales transactions in the five days prior to earnings announcements of 913 Nasdaq-listed firms. The tests provide evidence of informed trading in pre-announcement short-selling because they reveal that abnormal short-selling is significantly linked to post-announcement stock returns. Also, the tests indicate that short-sellers typically are more active in stocks with low book-to-market valuations or low SUEs. The levels of pre-announcement short-selling, however, mostly appear to reflect firm-specific information rather than these fundamental financial characteristics. We believe that these results should encourage financial market regulators to consider providing more extensive and timely disclosures of short-selling to investors.