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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Innovative Houston-area hardtech startup closes $5M seed round

fresh funding

Conroe-based hardtech startup FluxWorks has closed a $5 million seed round.

The funding was led by Austin-based Scout Ventures, which invests in early-stage startups working to solve national security challenges.

Michigan Capital Network also contributed to the round from its MCN Venture Fund V. The fund is one of 18 selected by the Department of Defense and Small Business Administration to participate in the Small Business Investment Company Critical Technologies Initiative, which will invest $4 billion into over 1,700 portfolio companies.

FluxWorks reports that it will use the funding to drive the commercialization of its flagship Celestial Gear technology.

"At Scout, we invest in 'frontier tech' that is essential to national interest. FluxWorks is doing exactly that by solving critical hardware bottlenecks with its flagship Celestial Gear technology ... This is about more than just gears; it’s about strengthening our industrial infrastructure," Scout Ventures shared in a LinkedIn post.

Fluxworks specializes in making contactless magnetic gears for use in extreme conditions, which can enhance in-space manufacturing. Its contactless design leads to less wear, debris and maintenance. Its technology is particularly suited for space applications because it does not require lubricants, which can be difficult to control at harsh temperatures and in microgravity.

The company received a grant from the Texas Space Commission last year and was one of two startups to receive the Technology in Space Prize, funded by Boeing and the Center for the Advancement of Science in Space (CASIS), in 2024. It also landed $1.2 million through the National Science Foundation's SBIR Phase II grant this fall.

Fluxworks was founded in College Station by CEO Bryton Praslicka in 2021. Praslicka moved the company to Conroe 2024.

5 Houston scientists named winners of prestigious Hill Prizes 2026

prized research

Five Houston scientists were recognized for their "high-risk, high-reward ideas and innovations" by Lyda Hill Philanthropies and the Texas Academy of Medicine, Engineering, Science and Technology (TAMEST).

The 2026 Hill Prizes provide seed funding to top Texas researchers. This year's prizes were given out in seven categories, including biological sciences, engineering, medicine, physical sciences, public health and technology, and the new artificial intelligence award.

Each recipient’s institution or organization will receive $500,000 in direct funding from Dallas-based Lyda Hill Philanthropies. The organization has also committed to giving at least $1 million in discretionary research funding on an ad hoc basis for highly-ranked applicants who were not selected as recipients.

“It is with great pride that I congratulate this year’s Hill Prizes recipients. Their pioneering spirit and unwavering dedication to innovation are addressing some of the most pressing challenges of our time – from climate resilience and energy sustainability to medical breakthroughs and the future of artificial intelligence,” Lyda Hill, founder of Lyda Hill Philanthropies, said in a news release.

The 2026 Houston-area recipients include:

Biological Sciences: Susan M. Rosenberg, Baylor College of Medicine

Rosenberg and her team are developing ways to fight antibiotic resistance. The team will use the funding to screen a 14,000-compound drug library to identify additional candidates, study their mechanisms and test their ability to boost antibiotic effectiveness in animal models. The goal is to move toward clinical trials, beginning with veterans suffering from recurrent infections.

Medicine: Dr. Raghu Kalluri, The University of Texas MD Anderson Cancer Center

Kalluri is developing eye drops to treat age-related macular degeneration (AMD), the leading cause of vision loss globally. Kalluri will use the funding to accelerate studies and support testing for additional ocular conditions. He was also named to the National Academy of Inventors’ newest class of fellows last month.

Engineering: Naomi J. Halas, Rice University

Co-recipeints: Peter J. A. Nordlander and Hossein Robatjazi, Rice University

Halas and her team are working to advance light-driven technologies for sustainable ammonia synthesis. The team says it will use the funding to improve light-driven catalysts for converting nitrogen into ammonia, refine prototype reactors for practical deployment and partner with industry collaborators to advance larger-scale applications. Halas and Nordlander are co-founders of Syzygy Plasmonics, and Robatjazi serves as vice president of research for the company.

The other Texas-based recipients include:

  • Artificial Intelligence: Kristen Grauman, The University of Texas at Austin
  • Physical Sciences: Karen L. Wooley, Texas A&M University; Co-Recipient: Matthew Stone, Teysha Technologies
  • Public Health: Dr. Elizabeth C. Matsui, The University of Texas at Austin and Baylor College of Medicine
  • Technology: Kurt W. Swogger, Molecular Rebar Design LLC; Co-recipients: Clive Bosnyak, Molecular Rebar Design, and August Krupp, MR Rubber Business and Molecular Rebar Design LLC

Recipients will be recognized Feb. 2 during the TAMEST 2026 Annual Conference in San Antonio. They were determined by a committee of TAMEST members and endorsed by a committee of Texas Nobel and Breakthrough Prize Laureates and approved by the TAMEST Board of Directors.

“On behalf of TAMEST, we are honored to celebrate the 2026 Hill Prizes recipients. These outstanding innovators exemplify the excellence and ambition of Texas science and research,” Ganesh Thakur, TAMEST president and a distinguished professor at the University of Houston, added in the release. “Thanks to the visionary support of Lyda Hill Philanthropies, the Hill Prizes not only recognize transformative work but provide the resources to move bold ideas from the lab to life-changing solutions. We are proud to support their journeys and spotlight Texas as a global hub for scientific leadership.”

Investment bank opens new Houston office focused on energy sector

Investment bank Cohen & Co. Capital Markets has opened a Houston office to serve as the hub of its energy advisory business and has tapped investment banking veteran Rahul Jasuja as the office’s leader.

Jasuja joined Cohen & Co. Capital Markets, a subsidiary of financial services company Cohen & Co., as managing director, and head of energy and energy transition investment banking. Cohen’s capital markets arm closed $44 billion worth of deals last year.

Jasuja previously worked at energy-focused Houston investment bank Mast Capital Advisors, where he was managing director of investment banking. Before Mast Capital, Jasuja was director of energy investment banking in the Houston office of Wells Fargo Securities.

“Meeting rising [energy] demand will require disciplined capital allocation across traditional energy, sustainable fuels, and firm, dispatchable solutions such as nuclear and geothermal,” Jasuja said in a news release. “Houston remains the center of gravity where capital, operating expertise, and execution come together to make that transition investable.”

The Houston office will focus on four energy verticals:

  • Energy systems such as nuclear and geothermal
  • Energy supply chains
  • Energy-transition fuel and technology
  • Traditional energy
“We are making a committed investment in Houston because we believe the infrastructure powering AI, defense, and energy transition — from nuclear to rare-earth technology — represents the next secular cycle of value creation,” Jerry Serowik, head of Cohen & Co. Capital Markets, added in the release.

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This article originally appeared on EnergyCaptialHTX.com.

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