Specialist shareholder activists and their impact on campaign success and target firm value
研究分析了四种专业程度的股东积极主义者类型，发现更高专业程度能提高运动成功概率和短期市场反应，但长期股东回报和经营业绩出现逆转，专业程度最高的类型长期表现最差。
Shareholder activists vary in investment style, expertise, time horizon, incentives, and engagement mode. This study examines four activist types, namely, Exclusive, Substantial, Limited, and Non-specialists, classified by degree of specialism. Using a U.S. sample of 3,903 activist campaigns (2008–2021), we analyze how specialism shapes campaign demands, tactics like Wolf Packs, and outcomes. We find that higher activist specialism significantly influences campaign themes and increases the likelihood of campaign success. Market reactions to campaign announcements are positively associated with specialism, with Exclusive specialists generating the highest abnormal returns. However, analysis of long-term shareholder returns and operating performance reveals a reversal of these initial gains over the three-year post-campaign period. Exclusive specialists underperform Non-specialists in long-term shareholder value and operating performance, though they outperform other specialist categories in limiting value deterioration. The reversal from short-term gains to long-term losses appears driven by specialists' preference for campaign themes that yield immediate payoffs but undermine long-term value. In contrast, fewer specialised activists often secure partial success through messy compromises that also erode long-term shareholder value. Robustness tests almost fully confirm the validity of these findings.