Based on his current spending, Campaign Media Analysis Group (CMAG), a service that monitors political advertising, predicts Obama's advertising campaign will surpass the USD 188 million Bush spent in his 2004 campaign by early next week.

With advertisements running unabatedly on all local and national broadcast networks and even on video games and his own dedicated satellite channels, the Democrat nominee is out-advertising his Republican rival McCain nationwide by a ratio of at least 4-to-1, the New York Times said, citing CMAG.

The huge gap has been made possible by Obama's decision to opt out of the federal campaign finance system, which provides Presidential nominees USD 84 million in public money and prohibits them from spending any amount above that from their party convention to Election Day.

McCain, however, is participating in the system.

Obama, who has earlier promised to participate in it, is expected to announce in the next few days that he has raised more than USD 100 million in September, a figure that would shatter fund-raising records.