Senator Hillary Clinton has loaned her own campaign $5m as it struggles to compete with the record sums being raised by the Obama campaign.
Several campaign aides have also decided to work without pay.
The news comes as both campaigns claimed victory in winning delegates from Super Tuesday's primaries.
The admission that Senator Clinton had invested the substantial sum of $5m from her own resources to fund her campaign last month came in a press conference last night.
Senator Clinton said: 'I loaned it because I believe very strongly in this campaign.'
It was also revealed that some of Mrs Clinton's senior aides are working without pay this month. The ABC network quoted the campaign's Communications Director, Howard Wolfson, as saying the move was 'a show of solidarity with Hillary Clinton'.
Last month, Senator Obama's campaign raised $32m compared to $13m raised by the Clinton campaign.
Estimates by media organisations show Senator Clinton is four pledged delegates ahead of Mr Obama (right)after Super Tuesday's primaries.
Analysis of the popular vote shows that out of 14.6m votes cast, less than 1% of the vote or just over 130,000 votes separated Senator Obama from Senator Clinton.
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