Houston founder shares how he's using tech to make digital media more effective and equitable

houston innovators podcast episode 173

This month, Mark Walker is celebrating his company's one year anniversary of going public — only the ninth Black-founded business to accomplish this feat on a U.S. stock exchange. Photo courtesy

After working in both sides of the advertising world, Mark Walker thought he could reimagine a platform that would be more efficient and equitable.

Walker co-founded his company, Direct Digital Holdings, an adtech platform, after serving in several roles — from an early hire at Houston digital media startup Questia to business development director at NRG Energy and COO of EBONY Media. He shares on the Houston Innovators Platform how he took this experience in tech, advertising, and media to create his company's platform.

"NRG Energy gave me a top-down view of the value chain, and Ebony gave me a bottoms-up view of the value chain of how media is purchased," Walker says on the show. "At Direct Digital Holdings, we help companies buy and sell media — and we leverage technology to do it. It's really the culmination of both of those experiences."

With over 30,000 publishers on its platform, Direct Digital makes it easier for its core customers — middle market companies looking to buy into the digital media ecosystem — to tap into these opportunities without the tech know-how they might otherwise need. Walker explains that at EBONY, he saw how small to midsize publications — especially the multicultural ones — were being left out on the ad selling side of the equation. The Direct Digital platform bridges the gap on each end.

Founded in 2018 in partnership with Keith Smith, who went through similar professional experiences, Direct Digital went public exactly one year ago after growing the company through strategic M&A activity. Walker says the decision to IPO made the most sense for his company — though it wasn't an easy process. Direct Digital is only the ninth company founded by a Black entrepreneur to go public on a US stock exchange.

"If you think the process is hard — it actually is," Walker says on the journey to IPO. "We were a privately held company, and we knew we had a good growth trajectory and we looked a couple different options. We decided to go public in a very traditional way."

Walker explains there were some risks involved, but the co-founders ultimately decided to shy away from adding in investors who might not have the same ideas for the company's future.

Direct Digital has been a Houston company from the star — despite the city not being home to a booming adtech ecosystem. Instead, Houston — with its collection of Fortune 500 companies and rich diversity — has allowed the business to stand out.

"If you look at and reflect on how our company has been built — from our board of directors to our leadership and management team — we're a majority minority organization all the way across the board," Walker says. "Diversity is very important to us. It's the lifeblood of our business — especially because we're serving publishers in those communities in big way. And moreso, we think you get the best product, thoughts, and ideas from a diverse workforce, and Houston fits right into that mold for us."

Walker shares more about his company's future, advice on IPO, and what all he's watching in adtech — from AI to streaming — on the podcast. Listen to the interview below — or wherever you stream your podcasts — and subscribe for weekly episodes.


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6 Houston startups disrupting industries with innovative technology

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Houston is no stranger to technology that's shaping the future. As the longtime location of NASA Johnson Space Center to home base for new ventures disrupting industries with their technology, the Bayou City has had its finger on the pulse of what's new and next for decades.

The Deep Tech Business category in our 2025 Houston Innovation Awards will honor an innovative startup providing technology solutions based on substantial scientific or engineering challenges, including those in the AI, robotics and space sectors.

Six deep tech companies have been named finalists for the 2025 award. They range from a company developing predictive software to accelerate the energy transition to a new venture that's developing humanoid robots.

Read more about these businesses, their founders and their breakthrough technologies below. Then join us at the Houston Innovation Awards on Nov. 13 at Greentown Labs, when the winner will be unveiled.

Tickets are now on sale for this exclusive event celebrating Houston Innovation.

ARIX Technologies

Industrial and robotics company ARIX Technologies is an integrated robotics and data analytics company that delivers inspection services. Its ARIX VENUS robot combines aerospace-grade engineering, advanced non-destructive testing (NDT) and AI-powered analytics to detect hidden corrosion under insulation for the downstream energy, petrochemical, and chemical processing sectors.

ARIX was founded in 2017 by Dianna Liu, a former ExxonMobil engineer. Craig Mallory serves as CEO. The company reports that it is scaling deployments with major Gulf Coast refineries, expanding its analytics platform to include predictive corrosion modeling and growing a global partner program.

Little Place Labs

Space tech company Little Place Labs is developing an AI, machine-learning software across a network of satellites that can provide insights from space in under seven minutes.

The company was founded in 2022 by CEO Bosco Lai and CTO Gaurav Bajaj. The company recently received an award from the U.S. Space Force that will support it in deploying multiple applications and products onto more than 55 satellites over the next 36 months for both national security and commercial use cases. The company won the Security, GovTech & Space competition at the SXSW Pitch showcase last year.

Newfound Materials

Newfound Materials has developed a predictive synthesis software platform for accelerating the discovery of novel materials for critical energy applications, such as batteries, magnets, catalysts, and more. It guides users on the best experiments to try in the lab to optimize the synthesis of their materials.

Newfound Materials was founded in 2024 by CEO Matthew McDermott and participated in the inaugural Activate cohort. The company plans to release a public web app soon. It also has plans to raise a pre-seed or angel round.

Paladin Drones

Paladian develops drone-as-first-responder (DFR) systems for public safety. Its technology gives first responders live aerial video before teams arrive, enabling quicker decisions, better resource allocation and reduced false alarms.

The company was founded in 2018 by Divyaditya Shrivastava and participated in the Y Combinator accelerator that year. The company raised a $5.2 million seed round in 2024 and another round for an undisclosed amount earlier this year. In the future, it plans to expand its DFR deployments into more cities, offer new payload delivery capabilities (like delivering Narcan and life vests), and enhance deconfliction features.

Persona AI

Persona AI is building modularized humanoid robots that aim to deliver continuous, round-the-clock productivity and skilled labor for "dull, dirty, dangerous, and declining" jobs.

The company was founded by Houston entrepreneur Nicolaus Radford, who serves as CEO, along with CTO Jerry Pratt and COO Jide Akinyode. It raised eight figures in pre-seed funding this year and also expanded its operations at the Ion. The company is developing its prototype of a robot-welder for Hyundai's shipbuilding division, which it plans to unveil in 2026.

Tempest Droneworx

Tempest Droneworx provides real-time intelligence collected through drones, robots and sensors. Its Harbinger software platform shares data through a video game engine and aims to provide teams with early warning and insight to help them make decisions faster.

The company was founded in 2021 by CEO Ty Audronis and COO Dana Abramovitz. It participated in the Mass Challenge Air Force Labs and won the Best Speed Pitch at SXSW earlier this year. The company is currently raising a $2.5M seed round.

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The Houston Innovation Awards program is sponsored by Houston Community College, Houston Powder Coaters, FLIGHT by Yuengling, and more to be announced soon. For sponsorship opportunities, please contact sales@innovationmap.com.


Houston has the lowest inflation problem in the U.S., new study finds

Money Talk

Despite the national inflation rate sitting at 3 percent as of September 2025, the impact of inflation on Houston and the surrounding area isn't as severe as the rest of the U.S., a new study has revealed.

Houston-The Woodlands-Sugar Land ranked as the metro with the smallest inflation problem in the U.S. in WalletHub's October 2025 "Changes in Inflation by City" report.

The study tracked inflation changes for 23 major metropolitan statistical areas (MSAs) using Consumer Price Index data from the latest month available and compared to data from two months prior. The analysis also factored in inflation data from last year to analyze both short- and long-term inflation changes.

Compared to two months ago, the inflation rate in Houston fell by 0.1 percent, and local inflation is only 1.10 percent higher than it was a year ago, WalletHub said.

Houston residents may be feeling the sting a lot less than they did in January 2024, when WalletHub said the city had the 7th highest inflation rate in the country. And yet, Houstonians are increasingly concerned with the economy and its effects on inflation, a recent University of Houston survey found.

A separate WalletHub study named Texas the No. 1 most "financially distressed" state in the U.S. for 2025, adding to the severity of Texans' economical woes.

U.S. cities with the worst inflation problems

Denver-Aurora-Lakewood, Colorado topped the list as the city with the No. 1 worst inflation problem as of September. The Denver metro saw a 1 percent uptick in inflation when compared to two months prior, and it's 3.10 percent higher than it was a year ago.

Elsewhere in Texas, WalletHub ranked Dallas-Fort Worth-Arlington as the metro with the 8th lowest inflation problem nationwide. That's a fair shift from a previous report from June 2025 that ranked DFW the No. 1 U.S. metro with the lowest inflation issues.

The top 10 metros where inflation has risen the most as of September 2025 are:

  • No. 1 – Denver-Aurora-Lakewood, Colorado
  • No. 2 – Los Angeles-Long Beach-Anaheim, California
  • No. 3 – Chicago-Naperville-Elgin, Illinois-Indiana-Wisconsin
  • No. 4 – Boston-Cambridge-Newton, Massachusetts-New Hampshire
  • No. 5 –Minneapolis-St. Paul-Bloomington, Minnesota-Wisconsin
  • No. 6 – (tied) Philadelphia-Camden-Wilmington, Pennsylvania-New Jersey-Delaware-Maryland and Washington-Arlington-Alexandria, D.C.-Virginia-Maryland-West Virginia
  • No. 8 – Anchorage, Alaska
  • No. 9 – New York-Newark-Jersey City, New York-New Jersey-Pennsylvania
  • No. 10 – San Diego-Carlsbad, California
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This article originally appeared on CultureMap.com.

Axiom Space taps solar array developer for first space station module

space contract

Houston-based Axiom Space is making progress on developing its commercial space station.

The company awarded Florida-based Redwire Corporation a contract to develop and deliver roll-out solar array (ROSA) wings to power the Axiom Payload Power Thermal Module (AxPPTM), which will be the first module for the new space station.

AxPPTM will initially attach to the International Space Station. AxPPTM will later separate from the ISS and rendezvous with Axiom’s Habitat 1 (AxH1) on orbit. Eventually, an airlock, Habitat 2 (AxH2) and finally the Research and Manufacturing Facility (AxRMF) will be added to the first two Axiom modules.

AxPPTM is anticipated to launch toward the end of 2027. The two-module station (AxPPTM and AxH1) is expected to be operational as a free-flying station by 2028, and the full four-module station around 2030.

The modules will be integrated and assembled at Axiom Space’s Assembly and Integration facility, making them the first human-rated spacecraft built in Houston.

Redwire’s ROSA technology was originally developed for the ISS, according to Space News. It has yielded a 100 percent success rate on on-orbit performance. The technology has also been used on NASA’s Double Asteroid Redirection Test mission, the Maxar-built Power and Propulsion Element for the Artemis Lunar Gateway and Thales Alenia Space’s Space Inspire satellites.

“As a market leader for space power solutions, Redwire is proud to be selected as a strategic supplier to deliver ROSAs for Axiom Space’s first space station module,” Mike Gold, Redwire president of civil and international space, said in a news release. “As NASA and industry take the next steps to build out commercial space stations to maintain U.S. leadership in low-Earth orbit, Redwire continues to be the partner of choice, enabling critical capabilities to ensure on-orbit success.”

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