Sen. Bernie Sanders of Vermont has been buoyed by a massive small donor base. (AP Photo/Michael Dwyer)

The top Democratic presidential contenders are continuing to outpace their Republican counterparts when it comes to raising money directly for their campaigns, according to third-quarter fundraising totals that  have been announced so far.

Former secretary of state Hillary Rodham Clinton pulled in $28 million, and Sen. Bernie Sanders of Vermont collected $26 million over the summer months, beating out the top raiser to date on the GOP side: retired neurosurgeon Ben Carson, who scooped up $20.2 million.

The other Republican candidates, who have announced their totals, trail behind: Sen. Ted Cruz of Texas ($12.2 million), Sen. Marco Rubio of Florida ($6 million) and Sen. Rand Paul of Kentucky ($2.5 million). The rest of the GOP field – including former Florida governor Jeb Bush – have not yet revealed how much they raised in the third quarter of the year.

To date, the five Democratic candidates have reported raising $118.5 million for their campaign committees, while the 15 GOP candidates have pulled in $107 million. Candidates have until Oct. 15 to file their latest fundraising and spending reports with the Federal Election Commission.

The initial batch of fundraising reports point to a continuation of the trend that emerged in the spring quarter, when the Democratic candidates raised more money directly for their campaigns, while nearly 80 percent of the money raised to support GOP contenders went to super PACs and other independent groups. It is unclear how much money has gone to super PACs since June 30, as the groups do not have to file with the FEC until the end of January.

[2016 fundraising shows power tilting to groups backed by wealthy elite]

The large sums that Clinton and Sanders have collected for their campaigns underscore a structural advantage that could help the eventual Democratic nominee. While super PACs have inserted themselves into the 2016 White House contest in an unprecedented manner, the early exit of candidates such as former Texas governor Rick Perry and Wisconsin Gov. Scott Walker spotlights the need for candidates to have their own robust finance operations. That means creating a large pool of small donors, who will be key to generating the estimated $1 billion that each party’s candidate will need to raise by Election Day. So far, just Carson and Cruz appear to have amassed sizable small donor bases on the right.

The full picture of last quarter’s fundraising efforts will emerge next week when the candidates file their FEC reports. The buzzing question of the moment among Republican fundraisers: How much did Bush collect? His haul will be closely scrutinized as an indicator of the health of his candidacy at a time when the former governor is trying to boost his standing in the polls.

In his first quarter as a candidate, Bush raised $11.4 million in two weeks, pulling in donations at the hefty rate of $760,000 a day — the fastest pace of all the 2016 contenders, according to a Post analysis. He and three generations of Bush family members kept up a busy schedule of fundraisers throughout the summer months, headlining at least 58 events that ranged from a luncheon in tony Montecito, Calif., to a breakfast reception in Oklahoma City, according to news reports and invitations compiled by Sunlight’s Political Party Time. Both the former presidents Bush lent a hand: George W. Bush did at least three events and George H. W. Bush two.

Other takeaways on the 2016 money race:

  • Most candidates spent at an intense clip last quarter.

We are already seeing that many White House hopefuls were operating at steep burn rates during the summer, a notoriously slow fundraising period. On the Republican side, Carson spent 64 percent of the money he raised last quarter, while Rubio raced through 81 percent of the funds he pulled in, and Paul had a dangerous burn rate of 186 percent — spending nearly $2 for every $1 donated, according to calculations by The Post. On the left, Clinton went through nearly 89 percent of the funds she raised, while Sanders spent just 45 percent of contributions that came in.

Numbers we’re watching for: How much cash Cruz and Bush had in the bank at the end of September.

[Hillary Clinton spent roughly 90 percent of the money she raised over the summer]

  • Sanders has a massive small donor operation.

The senator from Vermont has already outpaced where President Obama was at this point in his campaigns when it comes to the number of contributions, surpassing 1.3 million separate donations at the end of last month. A staggering 650,000 individuals have given Sanders money already.

Number we’re watching for: the total individuals who have given money to Clinton. At the end of June, she had 250,000 contributors.

  • Cruz is expanding his own small donor machine.

The senator from Texas has collected 362,300 contributions through the end of September, and 6,000 donors have signed on to give him money every month. Those “sustainers” provide enough revenue to cover all expenses every month for now for Cruz’s entire field operation across the country, the campaign said. Cruz also launched a social crowd-funding platform this month that encourages donors to bundle small contributions online.

Numbers we’re watching for: how much Bush and Rubio raised in small contributions.