Bloomberg BNA:

Campaign spending by super political action committees and other outside groups fell sharply this month in the presidential primary race, with money shifting to congressional races instead, according to reports on independent campaign expenditures filed with the Federal Election Commission (FEC) and analyzed by Bloomberg BNA.

Independent expenditures reported in the presidential race reached a total of just $2.25 million since April 1, compared to a total of nearly $28 million in such spending for the month of March.

Outside spending in congressional races reached more than $9.1 million so far this month, with more than $8.3 million going to key Senate races. The April total, so far, is already significantly above the $6.1 million spent in congressional races in all of March.

Reports of large independent expenditures—defined by the FEC as spending on television ads and other messages advocating for votes for or against candidates—are required to be filed by all outside spending groups. In the weeks before an election, these reports must be filed within 24 hours of when the money is spent, providing a gauge of the intensity and targets of outside campaign spending as the election approaches.