The group, Ready for Hillary, is an independent effort and does not have the support of Clinton herself, but has signed on some Clinton allies to help the cause.

One of those allies, longtime Clinton friend and adviser Harold Ickes, is meeting with two dozen "leading Democratic donors" for a Thursday breakfast to discuss the group's plans going forward. It held a similar event on Wednesday that drew 60 attendees.

The breakfast is being hosted by one of President Obama's top 2012 fundraisers, public relations executive Michael Kempner.

"The event is part of a big push to expand Ready for Hillary's finance committee and boost fundraising numbers before the June 30 filing deadline," a source told CNN.

"Those attending will hear from Harold Ickes and learn more about Ready for Hillary and why it is important to invest in the organization early as a means to put Hillary in the strongest position possible should she decide to run for president."

Clinton has not yet indicated her plans for 2016, but the Ready for Hillary super-PAC hopes to both urge her to run and establish the grassroots organization she'll need to tap if she does enter the race.

Every poll of the Democratic field shows the former secretary of State leading all other potential Democratic contenders by wide margins.