Former Florida governor Jeb Bush speaks at the Conservative Political Action Conference at National Harbor, Md., in February. (Carolyn Kaster/Associated Press)

This item has been updated.

MIAMI BEACH, Fla. -- Jeb Bush told about 350 of the top donors to his super PAC on Sunday evening that the organization has raised more money in its first 100 days than any other Republican operation in modern history, according to several people in attendance.

Bush did not say how much had been raised, but senior Republicans said they think his super PAC, Right to Rise, is on track to collect $100 million by the end of May. Those who heard Bush speak said it signals that he and his team are confident that they've amassed a sizable political fortune that will help bankroll his fledgling presidential aspirations.

Until now, George W. Bush has held the record for the best presidential fundraising debut of a GOP candidate. In the first four months of 1999, he brought in close to $37 million. Coming in second is Mitt Romney, who in the first quarter of 2007 raised more than $23 million, according to Federal Election Commission records. (Hillary Rodham Clinton beat them both, raising $36 million in the first quarter of 2007.)

Any comparison with past fundraising efforts is impossible, however, as Jeb Bush is the first White House hopeful to focus his early fundraising efforts on filling the coffers of a super PAC, which can accept unlimited donations from individuals and corporations.

The former Florida governor has spent the past several months on a nonstop fundraising blitz, headlining high-priced finance events at country clubs and resorts nationwide. Money has come in at such a rapid clip that his aides temporarily limited donations to $1 million.

Once Bush sets up an official campaign, it will be able to accept donations only up to $2,700 a person.

Bush spoke to his supporters at the 1Hotel, a new, eco-friendly establishment in Miami Beach with rooms that run into the four figures and include stunning vistas of the Atlantic Ocean.

Donors began meeting with Bush and his aides on Sunday afternoon, first by geographic regions, including one for the Northeast, one for the District of Columbia, Virginia and Maryland, another for Florida and another for donors from California. The festivities continued with a dinner that included chicken, where Bush referred twice to his historic sum, according to people in attendance.

The meetings will continue Monday with policy briefings led by his top aides, including David Kochel, his campaign manager in waiting; Sally Bradshaw, an aide at large; and Mike Murphy, a longtime GOP strategist who is expected to lead Right to Rise once Bush declares his candidacy and is legally obligated to no longer coordinate with the PAC.

But Bush isn't officially a candidate, meaning his top aides can still mix, mingle and coordinate. Murphy and Bradshaw were seen huddling in the hotel lobby for quite a while on Sunday afternoon. Republican super-lawyer Charlie Spies, who set up Bush’s super PAC and leadership PAC, was also in attendance.

Bush aides said that about 350 people signed up to attend the donor conference. Among the people spotted at the hotel were former Senate majority leader Bill First (R-Tenn.); C. Boyden Gray, a former ambassador and White House counsel; former senator George Lemieux (R-Fla.); Juleanna Glover, a veteran GOP operative and corporate consultant; longtime Bush friend and Miami-based lobbyist Al Cardenas and his son, David Cardenas; and Ana Navarro, another longtime Bush friend; former commerce secretary Carlos Gutierrez; and Adam Putnam, Florida's agriculture commissioner.

Several other donors were seen wearing name tags stating that they came from the District, Florida and Texas, among other places.