According to CNBC, incumbents held at least twice as much cash on hand as challengers in 11 of the 19 House races rated as toss-ups by The Cook Political Report with Amy Walter, based on Federal Election Commission data compiled by OpenSecrets. In every one of those races, the incumbent had the larger financial cushion, including Republican Rep. Tom Barrett in Michigan's 7th District, Republican Rep. Gabe Evans in Colorado's 8th District and Republican Rep. David Valadao in California's 22nd District.

Democratic incumbents also held sizable leads in some contests, with Rep. Marcy Kaptur of Ohio's 9th District, Rep. Jared Moskowitz of Florida and Rep. Vicente Gonzalez of Texas all reporting more cash than their Republican opponents. But challengers led in several races, including Christina Bohannan in Iowa's 1st District and Janelle Stelson in Pennsylvania's 10th District. CNBC said the latest quarterly reports covered activity through June 30, though some candidates have since filed additional reports tied to their states' primary calendars.