This study examines seasoned equity offering (SEO) announcements by listed and over-the-counter companies in Taiwan. The Boston Consulting Group (BCG) matrix is adopted to investigate short-run and long-run share price performance of SEO announcements under each matrix quadrant. The empirical results show that share prices generally drop after corporations announce an SEO. When divided according to the BCG matrix, the SEO announcements negatively influence the short-run share prices in the question, star, and dog quadrants. The question quadrant performs relatively favorably in long-run share price following an SEO announcement, whereas performance in the star and cow quadrants is poor. Notably, the question quadrant, which is characterized by high market growth rates and low relative market share, presents positive outcomes in long-run share price following SEO announcements. These results contradict the general consensus that announcing an SEO undermines share price.
