DOI: 10.26650/istjecon2026-1959057 ISSN: 2602-3954

The Impact of Rights Issues and Bonus Issues on Market Value: An Anomaly Study on Borsa Istanbul During Crisis and Post-Crisis Periods

Ferdi Çil, Mehmet Saraç
Show PDF Cite
Although the Efficient Market Hypothesis suggests that publicly available information should be rapidly reflected in stock prices, empirical market anomalies indicate that abnormal returns may arise under certain market conditions. This study examines the market response to rights issue and bonus issue announcements by companies listed on Borsa Istanbul (BIST), with particular emphasis on differences between the COVID-19 pandemic and post-pandemic periods. The sample consists of 20 companies, including 10 firms from 2021, representing the pandemic period, and 10 firms from 2023, representing the post-pandemic period. Using an event-study methodology, abnormal returns (AR) and cumulative abnormal returns (CAR) are examined over a 21-trading-day event window extending from 10 days before to 10 days after the announcement date. Abnormal returns are calculated relative to the BIST 100 Index. The findings indicate that market reactions exhibited different patterns across the two periods. In 2021, abnormal returns followed a volatile pattern, and CAR declined to −0,0430 by the end of the event window. A statistically significant negative abnormal return of −0,0452 was observed on Day +5 (t = −2,930, p = 0,003), while statistical significance was otherwise limited. In 2023, CAR followed a relatively more positive pattern, reaching 0,0515 on the announcement day and remaining positive at 0,0223 on Day +10. Although statistically significant abnormal returns were observed on several individual trading days, the overall event-window reaction was not statistically significant (t = 0,37). Overall, the findings suggest that investor responses to rights issue and bonus issue announcements are sensitive to prevailing market conditions and levels of uncertainty. However, the evidence does not support the existence of a persistent and systematically exploitable market anomaly or provide sufficient grounds for a robust rejection of semi-strong form market efficiency in either period.

More from our Archive