Fundraising for the rookie Illinois senator apparently outpaced collections for Clinton, The New York Times reported Friday.
While Obama's campaign didn't release an official amount, several major donors told the Times they thought it was in the $50 million range.
Campaign officials Thursday said Clinton, the senator from New York, raised $35 million. The Clinton camp said her ability to raise cash in the wake of 11 straight defeats showed her connection among voters and her ability to compete.
"It's an extraordinary number for us, $35 million in February alone," said Clinton campaign chairman Terry McAuliffe. "Hillary Clinton's not going anywhere. Hillary's going to one place. She's going to Denver as the Democratic Party nominee."
Ohio, Texas, Vermont and Rhode Island hold party primaries Tuesday.
Obama's large war chest presents a dilemma for him: If the Democratic front-runner, as Obama is now, becomes the presidential nominee will he accept public financing and abide by its spending limits? Obama indicated he would if Sen. John McCain of Arizona, the expected Republican nominee, does the same.