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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Houston leads Texas with 7 new National Academy of Inventors senior members

top honor

The University of Houston is now home to seven new senior members of the National Academy of Inventors.

The distinction honors active faculty, scientists and administrators from NAI member institutions that have demonstrated innovation and produced technologies that have “brought, or aspire to bring, real impact on the welfare of society,” according to the NAI. The members have also succeeded in patents, licensing and commercialization, and educating and mentoring.

According to UH, its seven new members represent the largest group from any single Texas institution this year, bringing the university's total senior member count to 46.

UH faculty also represented three of Houston's four new senior members in 2025. Six Houstonians were also named to the NIA's class of fellows late last year.

“This recognition affirms what we see every day at the University of Houston—bold, collaborative innovation focused on improving lives," Ramanan Krishnamoorti, vice president of energy at UH, said in a news release. "Having seven faculty members named Senior Members reflects our momentum and a culture where discovery moves beyond the lab into solutions that strengthen communities and drive economic growth.”

UH’s new senior members include:

  • Haleh Ardebili, endowed professor of mechanical and aerospace engineering and assistant vice president for Entrepreneurship and Startup Ecosystem. Ardebili develops flexible lithium batteries and holds four patents
  • Vemuri Balakotaiah, distinguished university chair and professor of chemical and biomolecular engineering. Balakotaiah holds is patents, with five pending, and develops mathematical models for the clean energy research.
  • Jakoah Brgoch, professor of chemistry. Brgoch develops next-generation inorganic materials and holds four patents.
  • Jose L. Contreras-Vidal, distinguished professor in electrical and computer engineering and director of UH’s NSF neurotechnology research center. Conreras-Vidal develops brain-machine interface technologies. He holds five patents, with two technologies advancing through clinical trials.
  • Preethi Gunaratne, professor in the department of biology and biochemistry and director of the UH Sequencing Core in UH’s College of Natural Sciences and Mathematics. Gunaratne holds five patents in biology and energy technologies and has made significant large-scale genome discoveries.
  • Jae-Hyun Ryou, professor of mechanical and aerospace engineering. Ryou holds 13 patents and has develops innovative semiconductor materials and devices for flexible electronics.
  • Yingcai Zheng, professor in applied geophysics and director of the UH Rock Physics Lab. Zheng's work focuses on energy production, geothermal development and carbon management strategies. He holds two patents.

Other Texas institutions also had strong showings this year. Additional new Texas senior members from NAI institutions include:

Texas A&M University

  • Guillermo Aguilar
  • Stavros Kalafatis
  • Narendra Kumar
  • Heng Pan
  • Xingyong Song
  • Yubin Zhou

Texas State University

  • Bahram Asiabanpour
  • Martin Burtscher
  • Nihal Dharmasiri
  • Alexander Kornienko
  • Ted Lehr
  • Christopher Rhodes

The University of Texas at Arlington

  • Brian H. Dennis
  • Nicholas Gans
  • Frederick M. MacDonnell
  • Charles Philip Shelor
  • Liping Tang

The University of Texas at San Antonio

  • Robert De Lorenzo
  • Marc Feldman
  • Daohong Zhou

The University of Texas at El Paso

  • XiuJun Li
  • Yirong Lin
  • David Roberson

Texas Tech University Health Sciences Center

  • Thomas John Abbruscato
  • Annette Louise Sobel
  • Sanjay K. Srivastava

Texas Tech University

  • Gerardo Games
  • Dy Dinh Le

Baylor University

  • David Jack

The University of Texas Rio Grande Valley

  • Upal Roy

This year's class is the largest since the NAI launched its senior member recognition program in 2018. The new senior members come from 82 NAI institutions ad hoe more than over 2,000 U.S. patents. Accoring to the NAI, it has 945 senior members who hold more than 11,000 U.S. patents today.

“This year’s senior member class is a truly impressive cohort. These innovators come from a variety of fields and disciplines, translating their technologies into tangible impact,” Paul R. Sanberg, president of NAI, added in a news release. “I commend them on their incredible pursuits and I’m honored to welcome them to the Academy.”

The Senior Member Induction Ceremony will honor the 2026 class at NAI’s Annual Conference June 1-4 in Los Angeles.

Texas takes the No. 1 spot on new energy resilience report

Ranking It

A new report by mineral group Texas Royalty Brokers ranks Texas as the No. 1 most energy-resilient state.

The study focused on four main sources of electricity in hydroelectric dams, natural gas plants, nuclear reactors and petroleum facilities. Each state was given an Energy Resilience Score based on size and diversity of its power infrastructure, energy production and affordability for residents.

Texas earned a score of 71.3 on the report, outpacing much of the rest of the country. Pennsylvania came in at No. 2 with a score of 55.8, followed by New York (49.1) and California (48.4).

According to the report, Texas produces 11.7 percent of the country’s total energy, made possible by the state’s 141,000-megawatt power infrastructure—the largest in America.

Other key stats in the report for Texas included:

  • Per-capita consumption: 165,300 kWh per year
  • Per-capita expenditures: $5,130 annually
  • Total summer capacity: 141,200 megawatts

Despite recent failures in the ERCOT grid, including the 2021 power grid failure during Winter Storm Uri and continued power outages with climate events like 2024’s Hurricane Beryl that left2.7 million without power, Texas still was able to land No. 1 on an energy resilience list. Texas has had the most weather-related power outages in the country in recent years, with 210 events from 2000 to 2023, according to an analysis by the nonprofit Climate Central. It's also the only state in the lower 48 with no major connections to neighboring states' power grids.

Still, the report argues that “(Texas’ infrastructure) is enough to provide energy to 140 million homes. In total, Texas operates 732 power facilities with over 3,000 generators spread across the state, so a single failure can’t knock out the entire grid here.”

The report acknowledges that a potential problem for Texas will be meeting the demands of AI data centers. Eric Winegar, managing partner at Texas Royalty Brokers, warns that these projects consume large amounts of energy and water.

According to another Texas Royalty Brokers report, Texas has 17 GPU cluster sites across the state, which is more than any other region in the United States. GPUs are specialized chips that run AI models and perform calculations.

"Energy resilience is especially important in the age of AI. The data centers that these technologies use are popping up across America, and they consume huge amounts of electricity. Some estimates even suggest that AI could account for 8% of total U.S. power consumption by 2030,” Winegar commented in the report. “We see that Texas is attracting most of these new facilities because it already has the infrastructure to support them. But we think the state needs to keep expanding capacity to meet growing demand."

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This article originally appeared on EnergyCapitalHTX.com.

6+ can't-miss Houston business and innovation events in March

where to be

Editor's note: March brings the return of some of Houston’s signature innovation events, plus insightful talks and celebrations in honor of Women's History Month. Here’s what not to miss and how to register. Please note: this article may be updated to include additional event listings.

March 3-4 — Houston MedTech Rodeo

Head to Armadillo Palace for the annual Houston MedTech Rodeo. The casual, Texas-themed conference brings together 350 medtech professionals who come from over 10 countries and 15 states to highlight Houston's growing medtech ecosystem. The event will feature panel discussions, startup showcases, networking sessions—plus, armadillo races, mechanical bull riding and live country music.

The event begins March 3 at Armadillo Palace on Kirby Drive. Register here.

March 4 – Humans of Healthcare

Houston Methodist Center for Innovation will present its new quarterly speaker series, Humans of Healthcare. The series will feature a panel of experts who will share about their career paths and discuss the nuances of the health care industry. This month's session will focus on IT. The panel will be moderated by Houston Methodist's Director of Innovation Murat Uralkan.

The event is Wednesday, March 4, from 5-6 p.m. at the Ion. Register here.

March 5 — The Future of Women in STEM

Celebrate Women's History Month at SUPERGirls SHINE Foundation's The Future of Women in STEM event, presented in partnership with the Ion. The event will feature speakers and panelists, including Kalila Winters Hines, senior public affairs advisor for Holland & Knight; Dr. Natacha Chough, NASA Johnson Space Center Flight Surgeon; and Andrea Course, rocket scientist and founder of Course Investments.

The event is Thursday, March 5, from 8:30-10 a.m. at the Ion. Register here.

March 10-12 — World Hydrogen & Carbon Americas

S&P Global Energy brings together two leading events—Carbon Management Americas and World Hydrogen North America—to form a new must-attend event for those in the hydrogen and carbon industries. More than 800 senior leaders from across the energy value chain will attend this event featuring immersive roundtable discussions, hands-on training, real-world case studies and unparalleled networking opportunities.

This event begins March 10 at the Marriott Marquis Houston. Register here.

March 20 — Ideas to Impact Accelerator Graduation and Showcase

Join Impact Hub Houston as it celebrates its inaugural Ideas to Impact Accelerator cohort. The 16-week accelerator is designed to help early-stage entrepreneurs validate their business models, strengthen confidence and gain traction. Hear short pitches and network with founders and mentors.

The event is Friday, March 20, from noon-2 p.m. at the Ion. Register here.

March 23-27 — CERAWeek 2026

CERAWeek 2026 will focus on "Convergence and Competition: Energy, Technology and Geopolitics." The industry's foremost thought leaders will convene in Houston to cultivate relationships and exchange transformative ideas during the annual event. CERAWeek 2026 will explore breakthroughs, cross-industry connections and powerful partnerships that are accelerating the transformation of the global energy system. 2026 highlights include an appearance by tech magnate Bill Gates.

This event begins March 23. Register here.

March 24-25 — 2026 Energy Venture Day and Pitch Competition

The Energy Venture Day and Pitch Competition, co-hosted by the Rice Alliance, Ion, HETI and TEX-E, offers two days of exciting pitches from more than 40 global energy ventures that are transforming the industry. On Tuesday, March 24, you can attend a fast-paced pitch preview event at the Ion, followed by the official Pitch Competition at 1 pm on Wednesday, March 25, at the George R. Brown Convention Center.

March 30-April 4 — H-Town Roundup

Celebrate innovation, entrepreneurship and collaboration at Houston Exponential's sixth-annual H-Town Roundup. During the free event series, previously known as Houston Tech Rodeo, attendees can expect insightful talks, workshops and networking events at venues across the city.

This event begins Monday, March 30. Register here.

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