ASE Technology Holding Co Ltd is a semiconductor assembly and testing firm. The company operates in segments: Packaging, Testing, and Electronic Manufacturing services. Of these, packaging services contributes the most revenue. It involves packaging bare semiconductors into completed semiconductors with improved electrical and thermal characteristics. The Testing Segment includes front-end engineering testing, wafer probing, and final testing services. In the EMS segment, the company designs, manufactures, and sells electronic components and telecommunication equipment motherboards. The company is based in Taiwan but garners over half its sales from firms in the United States.