Newark Mayor Cory Booker's special election campaign announced Thursday that he had a big fundraising quarter, pulling in $4.6 million for his Senate campaign between April and June.

Booker has $4.5 million cash on hand and a 40-point lead in the polls with just over a month until primary day.

He is a heavy favorite in both the Democratic primary on Aug. 13 and the Oct. 16 special election to succeed the late Sen. Frank Lautenberg (D-N.J.).

Booker has been building a national fundraising base with his campaign, pulling in more than 70 percent of his contributions from outside of New Jersey in the second quarter, which is what allows him to raise such a large sum. The campaign said 6,000 of Booker's 7,000 contributors were first-time donors.

His primary opponents have yet to release their fundraising numbers for the second quarter, which aren't due until Monday. Rep. Frank Pallone (D) is in the best shape to compete financially with Booker; he had $3.7 million stocked in his House campaign account when he launched his special-election campaign.

Also running are Rep. Rush Holt and state Assembly Speaker Sheila Oliver. On the GOP side, former gubernatorial candidate Steve Lonegan and Dr. Alieta Eck are competing.