As a former government contractor...I find this quite surprising. It's hard to find decent government contractors and even then it's usually just a few teams versus a whole company.
While I'm sure the Koch brothers will spend a large sum, the $900m isn't going to come from just them, that's the total goal of their political network, to be sourced from hundreds or thousands of donors. Their network spent nearly $400m during the 2012 elections.
