Siber Suçların Siber Saldırılara Maruz Kalan Şirketlerin Hisse Senedi Fiyatları Üzerindeki Etkileri
The Effects of Cybercrıme on The Stock Prıces of Companıes Exposed to Cyber Attacks

Summary/Abstract: Aim: Illegal activities committed using the Internet and other digital technologies are called cybercrime. Cybercrime includes a variety of online crimes, including unauthorized access to users' confidential data, DoS attacks, virus spread, online fraud and computer hacking. While important research has been done on the costs of cyber-attacks to companies, there has been little research that addresses the direct cost of a company to its shareholders, namely the impact of cybercrime on a company's stock price. This research explores the impact of the cybercrime threat on the stock prices of publicly traded companies. The study investigated the impact of cyberattack announcements about 17 publicly traded companies on stock prices. It was determined whether cyber crime news had statistically significant effects on the stock prices of publicly traded companies in the period 2012-2020. Method: This study investigated whether the prices and returns of stocks were statistically different and correlation coefficients between the periods after and before the 5-and 7-day cyberattacks decisively. Since stock prices affect each other on a daily basis, they were investigated by a paired t-test, and stock returns were investigated by indenependet sample t-test for 2 groups, since they are independent of each other. Findings: According to the results of the analysis, the changes in the shares of 10 companies for seven-day periods and 9 companies for five-day periodsin the periods before and after the attack were statistically significant. In stock returns, it was determined that the stock returns of six firms moved inversely in five-and seven-day periods, while the returns of 10 firms trended in different directions in 5-and 7-day periods. Results: According to the results of the study, it was determined that there were statistical differences in stock prices and returns after the time of the attack of companies that were subjected to cyber attacks. It can be said that cyber attacks directly affect firms.

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