A super political action committee supporting Kentucky Sen. Rand Paul's presidential campaign collected more than $3 million during the first six months of 2015, according to its filing with the FEC on Friday. America's Liberty PAC, which has the senator's blessing, had nearly $2.749 million cash on hand at the end of June.

One donor, however, accounted for nearly one-third of all cash collected during the first six months of 2015 by the super PAC. Jeff Yass, a Pennsylvania-based options trader and member of the Cato Institute's board of directors, contributed $1 million. Yass is one of the heads of the Susquehanna International Group, whose three leaders sunk nearly $7 million total into a failed Democratic candidate running for mayor in Philadelphia.

George Macricostas, a data company CEO, also donated more than $1 million.

Other notable donors include John Mackey, CEO of Whole Foods, Peter Schiff, a financial analyst and radio talk show host, Robert Arnott, a financial analyst, and John Agialaro, a writer and producer of three recent "Atlas Shrugged" films.

Paul's presidential campaign reported raising $7 million during its campaign's first quarter, bringing the total haul behind Paul to exceed $10 million.

Concerned American Voters announced it raised $1.88 million thus far.

"We were able to raise a significant amount in a relatively short time frame, which is a real indication to us that there's serious grassroots enthusiasm behind the Rand Paul candidacy," Matt Kibbe, senior adviser of the super PAC said in a statement.

Kibbe left the influential conservative group FreedomWorks to run the PAC.

This fundraising haul still puts the groups well behind a super PAC supporting former Florida Gov. Jeb Bush, which announced raising more than $100 million, earlier this month.