That would represent a dramatic acceleration in fund-raising by the Democratic presidential candidate from Vermont, who averaged raising about USD 11 million a month in the last quarter of 2015 -- USD 33 million for the period -- and it would indicate an ability to stay in the US race for the longer haul.
Campaigns are not required to report January totals just yet, so the Sanders announcement was seen as an effort to create a sense of growing momentum and broad-based appeal on the eve of the key Iowa caucuses.
Clinton's campaign said for all of 2015, she raised USD 112 million -- the most ever of any non-incumbent candidate in a non-election year.
She has set a goal for the first quarter of this year of USD 50 million, and has aggressively stepped up fund-raising efforts, deploying her husband Bill Clinton, her daughter Chelsea, and other high-profile surrogates.
The Sanders campaign said "nearly all" of its January take came from more than 770,000 online donors, whose donations averaged USD 27 apiece.
The Clinton campaign said earlier that 94 per cent of its fourth-quarter donations came in increments of USD 100 or less.
