There are 34 races (12 Senate and 22 House) where dark money groups have spent more than $1 million, and four Senate races where more than $10 million have been spent: Virginia ($19 million), Ohio ($13.1 million), Nevada ($11.7 million), and Wisconsin ($10.4 million).
In four House races where dark money tops $1 million and accounts for at least half of the outside money spent -- NY-28, CO-3, NY-22, and NY-23 -- 99.9 percent of the dark money has gone to support Republicans.
While 110 dark money groups have spent money on the election this year, the real money is being spent by just a handful of groups. The top five groups, all Republican-supporting, account for 64 percent of dark money spending. In fact, just two groups, Crossroads GPS and the U.S. Chamber of Commerce, account for 46 percent of the spending all by themselves.
And these numbers may only be a partial picture, because groups that don't disclose their donors also don't have to disclose their spending until a few weeks before an election. From the Sunlight Foundation's post:
These totals surely undercount the true amount of money these dark money groups have spent to influence elections, since they only have to disclose their election-oriented spending within 60 days of an election in House and Senate races, and following the national nominating conventions in the presidential race. Yet, when we looked at what Crossroads GPS was doing earlier in the cycle, we found that as of July 5, they had already announced $83 million in ad buys - more than they've reported in the disclosure window we are able to cover here.
You can see all the Sunlight Foundation's charts here.