With the increasingly complex challenges and issues in the real-world, designers are changing their roles in design practices and influencing organization hierarchy. Co-design becomes crucial to implement more successful design practices and has caught attention in academia. However, there are few studies about the demands or application of co-design in the real-world job market. This exploratory study analyzes 638 job postings across design practices (graphic/product /experience/service design, design research, design management) in the U.S. job market, and identifies five relevant and important co-design skill categories including research, knowledge transformation, collaboration, synthesis, visualization that employers expect from designers. Furthermore, this study presents and elaborates significant different frequencies and requirements of specific co-design skills across design practices, and also suggests that design employers are requiring more skills related to co-design. This paper can provide insights and recommendations of co-design skills to researchers and designers in this field.