Looks like Scytl is the largest election modernization provider in the US:
US Elections
Scytl Election Night Reporting, Scytl Poll Worker Management, Scytl Online Election Worker Training, Scytl Online Voter Education, Scytl Electronic Pollbook and Scytl Electronic Ballot Delivery.
Scytl has successfully delivered election modernization projects in the US since 2008, and most recently for the 2018 Midterm Elections, when over 70M voters from more than 900 U.S. counties successfully leveraged Scytl’s technology. Also, during 2016 US Presidential Election Scytl’s technology provided over 53 million registered voters and thousands of election staff across 28 states the benefits of more efficient, scalable and accessible election processes, consolidating Scytl as the leading election modernization provider in the United States.