Oct. 16 (Bloomberg) -- Democratic presidential candidates Hillary Clinton and Barack Obama are heading into the next 100 days of the campaign flush with cash, each with about three times as much as leading Republicans.

Clinton had a little less than $33 million at the end of September that can be used in the battle for the Democratic nomination, compared with almost $31 million for Obama. These numbers reflect money on hand reported by the campaigns late yesterday minus debts they owe. The Republican with the most primary-election cash was Rudy Giuliani, who had about $11 million.

Money in the bank is critical as candidates build their campaign operations and ramp up advertising ahead of primaries and caucuses that could begin as early as December. Most states will hold their contests by mid-February, so campaign advertising will escalate over the next few months.

``This is when voter impressions really count,'' said Stephanie Cutter, a Democratic strategist who worked for Massachusetts Senator John Kerry's 2004 presidential campaign. ``Those with money to have significant ad buys to define their candidacies have a significant leg up over the others.''

Obama today sent out a fundraising letter noting that Clinton out-raised him in the last three months. ``We must close that gap right now,'' he wrote.

Spending

Clinton, a New York senator, spent less than she brought in during the last quarter, while Obama, an Illinois senator, spent more. Clinton, 59, raised $23.7 million for the primary election during the period. Obama, 46, brought in $20 million.

The reports filed with the U.S. Federal Election Commission yesterday gave the first details of how Clinton and Obama have been spending their money during the last three months.

Clinton paid $15,000 for office rent to the William J. Clinton Foundation run by her husband, former President Bill Clinton. She spent $6 million on payroll, $1.7 million on media and almost $1 million on polling.

Clinton reported $2.3 million in debts, compared with $1.4 million for Obama.

Among Obama's expenses was a $9.30 charge for printing at the Clinton Library in Arkansas. He spent $5.6 million on payroll, $2.1 million on telemarketing and $3.7 million on media.

John Kerry

Obama is spending as much per week on Iowa TV as Kerry did less than a month before the 2004 caucus, said Evan Tracey, chief operating officer of Arlington, Virginia-based TNS Media Intelligence/Campaign Media Analysis.

In the third quarter, Clinton and Obama both increased their spending to similar rates, with the Clinton campaign burning through $22.6 million, compared with $21.5 million for the Obama campaign.

``Hillary herself is very clear that she wants to make sure that every dollar she spends is invested wisely,'' said Steve Grossman, one of her biggest fundraisers and a former Democratic National Committee chairman. ``She wants to make sure that she has the resources to be aggressive in each of the primary and caucus states.''

Among Republicans, former Massachusetts Governor Mitt Romney was second in cash on hand with $9.2 million. The governor's cash figures don't account for the more than $17 million he's loaned his campaign so far this year.

Biggest Spender

Romney, 60, is the biggest spender among Republicans, going through $21.3 million in the third quarter, compared with $13.3 million for Giuliani, 63, the former mayor of New York.

Because so many states have moved up their primaries and caucuses to Feb. 5 or before, the 2008 presidential race presents a new set of challenges for the campaigns. Candidates will have to move from contests in the early states of Iowa and New Hampshire into dozens of big states such as New York and California with expensive media markets.

Obama reported more new donors in the third quarter than he estimated at the beginning of the month. His total of 108,000 new contributors may have topped Clinton's estimate of more than 100,000.

He received $76,801 from employees of New York-based Viacom Inc., and $56,488 from employees of the law firm of Greenberg Traurig LLP, which formerly employed lobbyist Jack Abramoff, who is now in prison. Obama's campaign accepts donations from employees of firms that lobby, though not the lobbyists themselves.

Morgan Stanley

Clinton's biggest sources of money were New York-based Morgan Stanley, whose employees gave $209,970, and New York- based Goldman Sachs Group Inc., whose employees contributed $186,540.

Among Democrats, the closest competitor to Obama and Clinton in the so-called money primary is former North Carolina Senator John Edwards. He finished the third quarter with about $10 million in cash that can be used for the primaries, according to his campaign.

``Obama and Clinton are going to have plenty of money to be competitive,'' said Mike Feldman, who was a senior adviser to former Vice President Al Gore during his 2000 presidential campaign. ``When you look at the scale and scope of the operations that both of these campaigns have, it's staggering.''

To contact the reporters on this story: Kristin Jensen in Washington at kjensen@bloomberg.net; Jonathan D. Salant in Washington at jsalant@bloomberg.net

Last Updated: October 16, 2007 12:22 EDT