Hundreds of millions of dollars will flow into and out of super political action committees this election cycle. The question is, as campaigns come down to crunch time, why aren’t they spending even more than they are right now?

According to the Center for Responsive Politics, as of April 21, super PACs have collected more than $700 million this cycle, with independent expenditures of $286 million (there are other expenditures not included in that figure). A large part of that gap comes from Priorities USA Action, a super PAC supporting Hillary Clinton. The PAC has $45 million in cash on hand. Yes, Clinton is still a big favorite to win the Democratic nomination for president, and the PAC is probably saving its money for the general election. But you’d think the Clinton camp would still be a little more concerned than they are, having only 59 percent of all delegates distributed so far.