(CBS/AP) Sen. Hillary Rodham Clinton lent her presidential campaign $6.4 million over the past month, CBS News confirmed Wednesday, underscoring the financial advantage held by her rival, Barack Obama.

The money more than doubled Clinton's personal investment in her bid for the Democratic nomination. She gave her campaign $5 million earlier this year.

A campaign aide said Clinton gave her campaign another $5 million on April 11, more than a week before the Pennsylvania primary. She then again dipped into her personal wealth for $1 million last week and $425,000 on Monday, one day before the North Carolina and Indiana primaries. She has lent herself 11.42 million total for the campaign.

Clinton's campaign reported raising $10 million online after her Pennsylvania victory on April 22. Evidently, the money was not enough and her fundraising was unable to keep up with her expenses heading into Tuesday's contests.

Moreover, Obama has routinely outspent her in primary after primary and has shown little difficulty tapping his vast network of donors. He spent more than $7 million on advertising head of Tuesday's primaries in North Carolina and Indiana to her nearly $4 million.

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.

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