"Romney, Pawlenty, Roemer, and Cooper have all submitted paperwork and filed exploratory committees with the Federal Election Commission (FEC). Their exploratory committees are recognized by the FEC as such -- different from* campaign committees, PACs (political action committees), and 527 political committees: all different types of organizations that report to the FEC under different rules and abide by different, though generally similar, restrictions and fundraising limits.
Exploratory committees, according to the FEC, are organizations that support a candidate who is considering a run for office -- in campaign-law parlance, one who is 'testing the waters' of candidacy.
The functional difference is this: An exploratory committee doesn't have to report its finances to the FEC, whereas a campaign committee does. Until a campaign is official, the exploratory committee goes unscrutinized."
What's an Exploratory Committee?
The Atlantic:
