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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$50 million for Houston ibogaine research tops innovation news to know

News to know

Editor's note: The Houston innovation scene is entering 2026 with fresh funding for startups and major grants for innovative health treatments and neurological research. Here are the five most-read InnovationMap stories to start the new year, published Jan. 1-15, 2026:

1. Houston hospitals win $50M grant for ibogaine addiction treatment research

UTHealth Houston and UTMB will lead IMPACT, an initiative working toward ibogaine-based treatments for addiction and neurological issues. Photo via Pexels.

The Texas Health and Human Services Commission has awarded $50 million to UTHealth Houston in collaboration with The University of Texas Medical Branch at Galveston (UTMB Health) to co-lead a multicenter research trial to evaluate the effect of ibogaine, a powerful psychoactive compound, on patients suffering from addiction, traumatic brain injury and other behavioral health conditions. The funding will establish a two-year initiative—known as Ibogaine Medicine for PTSD, Addiction, and Cognitive Trauma (IMPACT)—and a consortium of Texas health institutions focused on clinical trials and working toward potential FDA-approved treatments. Continue reading.

2. Rice scientist earns $600K NSF award to study distractions in digital age

Kirsten Adam, a Rice psychologist, is studying how the brain refocuses in the age of screens, instant gratification and other lingering distractions. Photo via Pexels.

Rice University psychologist Kirsten Adam has received a $600,000 National Science Foundation CAREER Award to research how visual distractions like phone notifications, flashing alerts, crowded screens and busy workspaces can negatively impact focus—and how the brain works to try to regain it. Adam’s work will aim to clarify how the brain refocuses in the age of screens, instant gratification and other lingering distractions. The funding will also be used to train graduate students in advanced cognitive neuroscience methods, expand access to electroencephalography (EEG) and for public data sharing. Continue reading.

3. TMC launches new biotech partnership with Republic of Korea

The Texas Medical Center and KBIOHealth have launched the TMC Republic of Korea BioBridge. Photo via LinkedIn.

Houston's Texas Medical Center has launched its new TMC Republic of Korea BioBridge. The new partnership brings together the TMC with the Osong Medical Innovation Foundation, or KBIOHealth. The Biobridge aims to support the commercialization of Korean biotech and life science startups in the U.S., foster clinical research, and boost collaboration in the public, private and academic sectors. Continue reading.

4. CPRIT CEO: Houston’s $2B in funding is transforming cancer research and prevention

Kristen Doyle, CEO of the Cancer Prevention and Research Institute of Texas (CPRIT). Photo courtesy CPRIT.

With its plethora of prestigious health care organizations like the University of Texas MD Anderson Cancer Center, UTHealth Houston, and the Baylor College of Medicine, Houston sits at the heart of cancer research and prevention in Texas. Of course, it takes piles of cash to support Houston’s status as the state’s hub for cancer research and prevention. Much of that money comes from the Cancer Prevention and Research Institute of Texas (CPRIT). Data supplied by CPRIT shows organizations in Harris County gained $2.3 billion in institute funding from 2009 through 2025, or nearly $145 million per year. That represents almost 60 percent of the roughly $4 billion that CPRIT has granted to Texas institutions over a 16-year period. Continue reading.

5. 14 Houston startups starting 2026 with fresh funding

From groundbreaking energy leaders to growing space startups, here's who secured funding in the last six months of 2025. Photo via Getty Images

Houston startups closed out the last half of 2025 with major funding news. Here are 14 Houston companies—from groundbreaking energy leaders to growing space startups—that secured funding in the last six months of the year, according to reporting by InnovationMap and our sister site EnergyCapitalHTX.com. Continue reading.

​Planned UT Austin med center, anchored by MD Anderson, gets $100M gift​

med funding

The University of Texas at Austin’s planned multibillion-dollar medical center, which will include a hospital run by Houston’s University of Texas MD Anderson Cancer Center, just received a $100 million boost from a billionaire husband-and-wife duo.

Tench Coxe, a former venture capitalist who’s a major shareholder in chipmaking giant Nvidia, and Simone Coxe, co-founder and former CEO of the Blanc & Otus PR firm, contributed the $100 million—one of the largest gifts in UT history. The Coxes live in Austin.

“Great medical care changes lives,” says Simone Coxe, “and we want more people to have access to it.”

The University of Texas System announced the medical center project in 2023 and cited an estimated price tag of $2.5 billion. UT initially said the medical center would be built on the site of the Frank Erwin Center, a sports and entertainment venue on the UT Austin campus that was demolished in 2024. The 20-acre site, north of downtown and the state Capitol, is near Dell Seton Medical Center, UT Dell Medical School and UT Health Austin.

Now, UT officials are considering a bigger, still-unidentified site near the Domain mixed-use district in North Austin, although they haven’t ruled out the Erwin Center site. The Domain development is near St. David’s North Medical Center.

As originally planned, the medical center would house a cancer center built and operated by MD Anderson and a specialty hospital built and operated by UT Austin. Construction on the two hospitals is scheduled to start this year and be completed in 2030. According to a 2025 bid notice for contractors, each hospital is expected to encompass about 1.5 million square feet, meaning the medical center would span about 3 million square feet.

Features of the MD Anderson hospital will include:

  • Inpatient care
  • Outpatient clinics
  • Surgery suites
  • Radiation, chemotherapy, cell, and proton treatments
  • Diagnostic imaging
  • Clinical drug trials

UT says the new medical center will fuse the university’s academic and research capabilities with the medical and research capabilities of MD Anderson and Dell Medical School.

UT officials say priorities for spending the Coxes’ gift include:

  • Recruiting world-class medical professionals and scientists
  • Supporting construction
  • Investing in technology
  • Expanding community programs that promote healthy living and access to care

Tench says the opportunity to contribute to building an institution from the ground up helped prompt the donation. He and others say that thanks to MD Anderson’s participation, the medical center will bring world-renowned cancer care to the Austin area.

“We have a close friend who had to travel to Houston for care she should have been able to get here at home. … Supporting the vision for the UT medical center is exactly the opportunity Austin needed,” he says.

The rate of patients who leave the Austin area to seek care for serious medical issues runs as high as 25 percent, according to UT.

New Rice Brain Institute partners with TMC to award inaugural grants

brain trust

The recently founded Rice Brain Institute has named the first four projects to receive research awards through the Rice and TMC Neuro Collaboration Seed Grant Program.

The new grant program brings together Rice faculty with clinicians and scientists at The University of Texas Medical Branch, Baylor College of Medicine, UTHealth Houston and The University of Texas MD Anderson Cancer Center. The program will support pilot projects that address neurological disease, mental health and brain injury.

The first round of awards was selected from a competitive pool of 40 proposals, and will support projects that reflect Rice Brain Institute’s research agenda.

“These awards are meant to help teams test bold ideas and build the collaborations needed to sustain long-term research programs in brain health,” Behnaam Aazhang, Rice Brain Institute director and co-director of the Rice Neuroengineering Initiative, said in a news release.

The seed funding has been awarded to the following principal investigators:

  • Kevin McHugh, associate professor of bioengineering and chemistry at Rice, and Peter Kan, professor and chair of neurosurgery at the UTMB. McHugh and Kan are developing an injectable material designed to seal off fragile, abnormal blood vessels that can cause life-threatening bleeding in the brain.
  • Jerzy Szablowski, assistant professor of bioengineering at Rice, and Jochen Meyer, assistant professor of neurology at Baylor. Szablowski and Meyer are leading a nonsurgical, ultrasound approach to deliver gene-based therapies to deep brain regions involved in seizures to control epilepsy without implanted electrodes or invasive procedures.
  • Juliane Sempionatto, assistant professor of electrical and computer engineering at Rice, and Aaron Gusdon, associate professor of neurosurgery at UTHealth Houston. Sempionatto and Gusdon are leading efforts to create a blood test that can identify patients at high risk for delayed brain injury following aneurysm-related hemorrhage, which could lead to earlier intervention and improved outcomes.
  • Christina Tringides, assistant professor of materials science and nanoengineering at Rice, and Sujit Prabhu, professor of neurosurgery at MD Anderson, who are working to reduce the risk of long-term speech and language impairment during brain tumor removal by combining advanced brain recordings, imaging and noninvasive stimulation.

The grants were facilitated by Rice’s Educational and Research Initiatives for Collaborative Health (ENRICH) Office. Rice says that the unique split-funding model of these grants could help structure future collaborations between the university and the TMC.

The Rice Brain Institute launched this fall and aims to use engineering, natural sciences and social sciences to research the brain and reduce the burden of neurodegenerative, neurodevelopmental and mental health disorders. Last month, the university's Shepherd School of Music also launched the Music, Mind and Body Lab, an interdisciplinary hub that brings artists and scientists together to study the "intersection of the arts, neuroscience and the medical humanities." Read more here.

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