A couple of dozen people chatter and type in a seventh-floor office surrounded by a Houston skyline, powering Ted Cruz's campaign for president.

At least 75,000 supporters chipped in $26 million to help the freshman Texas senator fund the downtown office and otherwise spread his message of conservative overhaul to Republican voters. Of $17.3 million in itemized contributions, $9.2 million came from Texas. The Houston area, Cruz's home, gave $3 million.

But that's as of October, the most recent federal deadline for campaign finance report. The next is Sunday, when politicos will pounce for a look at the candidates' books.

So far, donor support has helped Cruz brazenly defy expectations and emerge as a leading contender for the GOP presidential nomination.

The revenue is slightly above average, but some political observers say its applications have been cutting-edge.

"He's spending top dollar on these modern campaign services," said Steve Jarding, a former manager of Democratic Senate campaigns and a Harvard University lecturer. "And it's really working."

Presidential candidates typically contract myriad private firms to research, design and manage outreach. Some experts say the Cruz campaign is leveraging donations to conduct a data-driven campaign unusual for a Republican.

"It looks more like a page out of the Democratic playbook than what we see traditionally with Republicans," said Anthony Corrado, a campaign finance scholar at the Brookings Institute.

Innovative digital strategies first emerged prominently in the presidential campaigns of Barack Obama and Howard Dean. Now embraced by Democrats, the techniques haven't been as effectively applied in GOP campaigns, Corrado said.

Of the $13 million spent by the Cruz campaign through October, about 40 percent went to traditional campaign ground operations, including $1.3 million in postage, $400,000 in airline tickets, $200,000 in facility fees to host events across the country and almost $1 million in payroll. Another $10,500 was spent on parking, $93,700 at hotels or motels, and $18,000 at restaurants.

Most of the remaining $8 million went to about a dozen companies for campaign services: $1.3 million in marketing, $1 million for fundraising and more than $800,000 for political strategy consulting. About $250,000 was spent on survey research and $750,000 went to donor modeling service.

"Modern campaigns are highly data driven," said Mark Jones, a fellow in political science at the Baker Institute. "You need a good consultant."

Gone are the days when a primetime TV ad was the best a campaign could do. In the digital age, tremendous research informs which Internet sites a campaign will run ads on and at what time of day.

Targeting audiences

The Cruz campaign turns out a steady flow of videos and sends daily fundraising emails to supporters that are timely and unique. Far more than its competitors, observers say the campaign targets narrow audiences through social media with concise messages scientifically formulate to each.

"From the start, they planned to make online outreach and voter profiling important," Corrado said.

For voter profiling help, the Cruz campaign contracted Cambridge Analytica for $750,000. The firm's website advertises that it collects "up to 5,000 data points on over 220 million Americans, and use more than 100 data variables to model target audience groups and predict the behavior of like-minded people."

According to Corrado, those data points include shopping records, subscriptions, affiliations, Internet use and social media behavior.

The campaign paid $1.3 million to The Lukens Company, which advertises tailored services designing and writing emails, digital ads phone scripts and mailed letters, and more than $1 million to Campaign HQ, a "conservative call center."

"These companies have huge voter databases that no campaign on its own could ever put together," Jones said.

And Cruz paid more than $2 million to Campaign Solutions, which claims on its website to have "raised more online money for Republican candidates, ballot initiatives, non-profit organization, and public affairs clients than any consulting firm in history."

"He needs this, and it's worked well for him," Jarding said. "He's not a mainstream candidate. Jeb Bush has the Bush apparatus. Cruz has this apparatus."

But this spending analysis neglects a major unofficial part of the Cruz campaign: super political action committees, entities formed independently by wealthy donors to back their favorite candidate.

Cruz enjoys the backing of four super PACs and several minor ones. Historically, candidates have been happy to have one.

While the official Cruz campaign made $26 million through October, its backing PACs raked in almost $40 million by July.

Finance filings due

Thanks to the 2010 U.S. Supreme Court decision in the Citizens United case, super PACs don't need to report the source of their revenue, making them the top purveyor of so-called "dark money" in politics.

But some sources of big pro-Cruz money have been forthcoming about their donations, revealing that four billionaires, including three from Texas, have provided the bulk of pro-Cruz super PAC funding.

The Texans include the Wilks brothers, who made their fortune in fracking, and Houston businessman Tony Neugebauer, who did not respond to requests for comment.

Everything officially known about current super PAC spending comes from a federal filing in July. The next is due Sunday and will reveal how the committees have dealt their funds in this heated elections.

According to Jarding, the emergence of PACs in the election process encouraged the growth of the general contractor-style campaign like Cruz's. In the later part of the last century, more than half of campaign spending went toward TV ads. Now PAC money sponsors most of the TV ads.

Jarding said that has freed campaign funds, which in turn have been invested into big data analysis and digital voter targeting techniques.

"Anyone who doesn't do it is not going to win," he said. "I don't think that's a good thing, by the way."