Among the others who contributed at the summit was personal-investment tycoon Charles Schwab, who committed to a seven-figure donation. Also at the summit, the brothers announced a new candidate training academy, Grassroots Institute, according to POLITICO.

The Kochs reportedly also are behind a voter database called Themis, similar to the Democrats' Catalist, and their network of groups is expected to spend roughly $400 million in this election cycle.