Sterling Group's AGS American Glass Services has acquired Elgin, Illinois-based commercial glazing contractor Mark Industries for undisclosed terms. Mark fabricates and installs commercial glass systems for warehouse, office, retail and other buildings throughout the greater Chicago area using in-house fabrication capabilities. Josh Cunningham, Mark's owner and president, has joined AGS and will continue to lead the business.

The deal extends AGS into the Chicago metropolitan market and places Mark near AGS's East Moline operations, creating opportunities to better serve customers across northern Illinois. Sterling launched AGS in July 2025 through its investment in Omni Glass & Paint and East Moline Glass, two Midwest glazing businesses that serve as the platform's core operating companies. The firm's goal is to build a commercial glazing and coatings platform across the Midwest.

AGS has since invested in platform infrastructure and centralized services. With the addition of Mark, AGS now has approximately 500 employees across 10 locations and believes it is one of the largest glazing contractors in the Midwest and one of the top glazing platforms in the US by revenue. AGS is headquartered in Oshkosh, Wisconsin, and its portfolio also includes Arrow Glass, Elite Glass & Metal and Cedar Rapids Glass Company.

It provides commercial glass installation, paint and coating services, tempered glass distribution and glass products for specialty vehicles. The company continues to pursue acquisitions in both existing and new markets.