The Republican lawmaker has more than $3.4 million in cash on hand.
In Monday visit, Mass. Dem will portray Shelley Moore Capito (R) as a friend to big banks.
The close fundraising comes as polls show David Purdue gaining ground on Rep. Kingston.
He released a new ad accusing Alexander of supporting "amnesty" for illegal immigrants.
True the Vote declared it has evidence of tampering in runoff records.
The North Carolina Democrat raised more than $3.6 million, her campaign said.
Dems fear that a drop-off in minority voters could severely cost them at the polls this fall.
Sen. Brian Schatz (D-Hawaii) appears to have the unlikely edge in bitter race.
She said he's “being led down a primrose path to political oblivion.”
Terri Lynn Land (R) bested Gary Peters (D) with help from $1.2 million in self-funding.