"With more than $149 million given to the group by super PACs and hybrid PACs, liberal consultant Waterfront Strategies claims the top spot among outside spending vendors in 2018. Waterfront’s dominant position isn’t particularly surprising, as it is an arm of the massive D.C. firm GMMB Consulting. Between GMMB and Waterfront, the two groups have combined to be the highest-paid consultant in each election cycle since 2012."
https://www.opensecrets.org/news/2019/01/political-consultants-making-millions-to-influence-elections/