A campaign aide said Hillary Rodham Clinton loaned herself $6.4 million in the past month.

The money more than doubles Clinton's personal investment in her bid for the Democratic nomination. Prior to Super Tuesday in February, Clinton loaned her campaign $5 million to keep up with rival candidate Barack Obama.

Obama has set records for fundraising, including $55 million in February and $40 million in March.

Obama has routinely outspent her in primary after primary. Clinton's campaign reported raising $10 million online after her victory April 22 in Pennsylvania. But Obama has shown little difficulty tapping his vast network of donors. He spent more than $7 million on advertising ahead of Tuesday's primaries in North Carolina and Indiana to her nearly $4 million.

In her speech after Tuesday's primaries in Indiana and North Carolina, she encouraged supporters to go to her Web site to donate to the campaign.

According to the latest campaign finance reports filed with the Federal Election Commission, Obama began the month of April with $42 million in the bank for the primary to Clinton's $9.3 million.

But Clinton had debts of $10.3 million at the start of the month, much of it money owed to her main polling, phone banking and advertising consultants.