Penelitian ini bertujuan untuk mengetahui pengaruh karakteristik transaksi merger dan akuisisi (M&A) serta karakteristik perusahaan terhadap abnormal return jangka panjang. Sampel penelitian terdiri dari 64 transaksi M&A dalam periode 2009-2021. Penelitian ini menunjukan bahwa terjadi abnormal return negatif pada saham perusahaan pengakuisisi pada seluruh periode pengukuran. Status target perusahaan privat berpengaruh positif dan signifikan terhadap BHAR. Deal-value relative size, ukuran perusahaan pengakuisisi, dan book to market ratio berpengaruh signifikan terhadap BHAR. Metode pembayaran tunai dan pandemi Covid-19 berpengaruh negatif dan signifikan terhadap BHAR. Perusahaan pengakuisisi dan investor perlu memperhatikan karakteristik transaksi dan perusahaan untuk mengoptimalkan nilai perusahaan bagi pemegang saham dan mendapatkan abnormal return yang positif di masa datang.

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This study aims to determine the effect of the firm and deal characteristics of mergers and acquisitions on long-term abnormal returns. The research sample consists of 64 M&A transactions in the 2009–2021 period. This study shows that there is a negative abnormal return on the acquirer company's shares in all measurement periods. The target status of private companies has a positive and significant effect on BHAR. The deal-value relative size, the size of the acquiring company, and the book-to-market ratio have a significant effect on BHAR. The cash payment method and the COVID-19 pandemic have had a negative and significant effect on BHAR. Companies and investors need to pay attention to the characteristics of transactions and companies to optimize company value for shareholders and get positive abnormal returns in the future.