Vermont senator and presidential candidate Bernie Sanders campaigns at the University of New Hampshire in Durham. (Photo by Preston Ehrler/SOPA Images/LightRocket via Getty Images)Preston Ehrler | LightRocket | Getty ImagesSen. Bernie Sanders’ campaign said Tuesday that it raised more than $25 million in the third quarter, a huge haul that will give the operation a boost as it jockeys for position near the top of the 2020 Democratic primary field.The $25.3 million taken in by the Vermont independent marks the biggest fundraising quarter for a Democratic presidential hopeful so far in the election. It tops the $18 million Sanders raised in the second quarter. His campaign has touted its ability to raise large sums from small individual donations rather than big-dollar fundraisers.The campaign did not say how much cash it had on hand at the end of September. It entered July with $27.3 million on hand — the most among Democratic candidates — setting Sanders up for a potentially long run in the primary.Sanders and his rivals started to release their third quarter fundraising figures Tuesday after the quarter ended. South Bend, Ind. Mayor Pete Buttigieg’s campaign took in more than $19 million in the same period.Sanders, who has promised an overhaul of the political and economic system, has run on a single-payer “Medicare for All” health care plan and proposals to tax the wealthy more heavily. He sits at 17.5% of support in a RealClearPolitics average of recent national polls, behind former Vice President Joe Biden and Sen. Elizabeth Warren, D-Mass.While his support has slipped nationally, the Vermont senator has consistently polled among the top candidates in key early nominating states such as New Hampshire and Nevada.On top of the $25.3 million raised in the third quarter, Sanders also transferred $2.6 million from other campaign accounts to his presidential operation. Subscribe to CNBC on YouTube.