Amkor Technology (AMKR) shares fell 5.79% in after-hours trading following the release of its third-quarter earnings report and announcement of a CEO transition. While the company beat analyst expectations for Q3, its fourth-quarter guidance came in below consensus estimates, likely contributing to the stock's decline.

For the third quarter, Amkor reported earnings of $0.51 per share, surpassing the FactSet analyst consensus of $0.43. Net sales reached $1.99 billion, up from $1.86 billion a year earlier and above the expected $1.93 billion. However, the company's Q4 outlook dampened investor enthusiasm, with projected earnings of $0.38 to $0.48 per share on net sales of $1.78 billion to $1.88 billion, falling short of analyst expectations of $0.42 EPS and $1.86 billion in revenue.

Adding to the news, Amkor announced that CEO Giel Rutten plans to retire at the end of the year, with COO Kevin Engel set to take the helm on January 1, 2026. While the company assured a smooth leadership transition, the combination of lower-than-expected guidance and the upcoming change in top management likely contributed to investor uncertainty, resulting in the after-hours stock price decline.