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 startup lands $10M to power up electrician staffing platform

money moves

Houston-based Buildforce, which provides a tech-enabled staff platform geared toward electricians and electrical contractors, has raised a $10 million Series A round led by Houston’s Saepio Capital.

Other investors in the round include Blue Heron Capital, Revolution’s Rise of the Rest Seed Fund, S3 Ventures and Chicago Ventures.

Buildforce says the funding will help fuel its national expansion and further development of its technology.

The startup, founded in 2019, connects electricians with electrical contractors for commercial and industrial construction projects. Buildforce’s mobile app helps electricians find and carry out work, and a web app helps electrical contractors find and manage electricians.

“This financing is a major milestone in furthering our mission to help people dedicated to a career in the construction trades lead more secure and fulfilling lives,” co-founder and CEO Moody Heard said in a news release.

Buildforce focuses solely on the electrical trade within the construction sector.

Nick Graziano, principal at Blue Heron, says the shortage of electricians is intensifying as demand for electricians accelerates, driven by data center construction, infrastructure development and energy transition initiatives.

The U.S. Bureau of Labor Statistics estimates the U.S. will need to hire about 80,000 new electricians per year through 2032 to catch up with demand. According to the National Electrical Contractors Association, the U.S. is grappling with a current shortage of 50,000 electricians.

A 2026 economic report from asset manager BlackRock says the electrical trade is expected to be the single fastest-growing employment category in the U.S. labor market over the next 10 years.

“Buildforce is capitalizing on a clear opportunity in America’s generational infrastructure buildout. We believe their mission to use technology to improve lives in the construction space will allow them to make a positive long-term impact on a large and important labor market,” added Jaan Bains, managing partner at Saepio Capital.

2 Houston companies tapped to build robots for Mars & more innovation news

Trending News

Editor's note: The biggest innovation headlines in July include robots for Mars, the launch of the Texas Stock Exchange, and cancer research funding. Below are the five most-read InnovationMap articles published July 15-31, 2026:

1. Houston space companies win NASA funding to build Mars exploration robots

Two Houston-area spacetech companies have landed a portion of a $17 million award from NASA to develop robots for exploring the surface of Mars, the agency announced. Houston-based Intuitive Machines and Webster, Texas-based MEI Technologies, which does business as Aegis Aerospace, were among the seven companies selected to receive the funding from NASA's Science Transport and Robotic Innovation for Deployment and Exploration (STRIDE) initiative. Continue reading.

2. New Texas Stock Exchange officially begins trading in Dallas

Two-step aside, New York Stock Exchange and Nasdaq. The Dallas-based Texas Stock Exchange, nicknamed Y’all Street, has kicked off live trading with five stocks — and lots of Lone Star ambition. “The Texas Stock Exchange aims to revitalize competition for [stock] issuers, establish the premier venue for listings, and create a world-class trading platform for all market participants,” the exchange says. The exchange — whose Texas-influenced nickname is a nod to New York City’s Wall Street — has collected at least $275 million in investments. Continue reading.

3. Rice, Houston Methodist award $90K for cancer research projects

Rice University’s Synthesis X Center, in partnership with the Houston Methodist Neal Cancer Center, announced earlier this month the organizations would award $90,000 in seed grant funding to two projects that could help fight cancer. One would ease the pain of chemotherapy, while the other could change the way the progression of leukemia is tracked. “We’re excited to be collaborating with the Neal Cancer Center to support collaborative, novel and interdisciplinary proposals to improve cancer care and outcomes,” Han Xiao, Rice professor of chemistry and the director of the SynthX Center, said. “Together, we can achieve translational excellence.” Continue reading.

4. London AI startup selects Houston for first U.S. office after $20M raise

London-based AI firm Applied Computing has announced a $20 million Series A round and a new office in Houston. The new Bayou City office is Applied Computing’s first in the United States and part of its North American expansion. The company is known for its Orbital AI platform, which is tailored for energy operations. The funding round was led by Houston-based KBR Inc., with participation from San Francisco-based Databricks Ventures. KBR’s investment was first announced in March. Continue reading.

Report: Houston ranks among 10 most affordable metros to raise a child

Raising a child is not an easy or inexpensive feat, but a new study has determined Houston parents have the 7th lowest childrearing costs in the country. SmartAsset's new report, "Cost of Raising a Child in Major U.S. Metros – 2026 Study," calculated year-over-year changes in the annual cost of raising a child (factoring in childcare, additional housing costs, food, transportation, medical costs and other necessities) in the 48 largest U.S. metro areas. Continue reading.

Venus Aerospace adds government, C-suite leaders following $91M raise​

new leaders

Fresh off its $91 million Series B, Houston-based Venus Aerospace has made several key additions and promotions to its leadership team.

The company says its expanded team will help it deploy its high-thrust rotating detonation rocket engine (RDRE), which completed its first U.S. flight test last summer.

"We flew the world's first high-thrust RDRE in just over four years on $80 million. We believe that makes it the fastest, most capital-efficient rocket engine program in history," Sassie Duggleby, co-founder and CEO of Venus Aerospace, said in a news release. "Adding this talent to our leadership team is how we bring that same discipline to the company itself, as we scale to meet the technical needs of defense and space customers who need range and speed legacy systems can't deliver."

The key hires include:

Lane Bodian, Vice President of Public Policy

Bodian previously served as the Principal Deputy Assistant Secretary of Defense for Legislative Affairs at the Pentagon.

Dan Rebnord, Director of Federal Government Relations

Rebnord most recently served as Senior Policy Advisor to a member of the Senate Armed Services Committee and previously worked in the Office of Legislative Affairs at the Department of Defense and as Staff Director for a national security subcommittee in the House of Representatives. Rebnord and Bodian will lead Venus' work with government stakeholders.

Tom Barron, Chief Operating Officer

Barron was promoted from his role as vice president of operations for Venus Aerospace. Before his time at Venus, he served as Special Assistant to the Secretary of Defense and consulted aerospace clients at McKinsey & Company. He also served as a U.S. Army Infantry and Special Forces officer.

Nick Cardwell, Chief Product Officer

Cardwell was promoted from his role as vice president of research and development. He previously held product and technology leadership roles at VC-backed tech companies in the San Francisco Bay Area and Austin.

Venus also named Cameron Taylor as its new vice president of operations, Sarah Boland Heine as its head of communications, Matt Stohr as its head of business development, and Sheila Menz as general counsel.

The company also announced a joint technology development agreement to advance the RDRE with defense giant Lockheed Martin last week. Through the partnership, Venus and Lockheed will focus on evaluating the RDRE's propulsion architecture in defense systems, specifically for precision fires applications where weapons are designed to accurately strike targets at long distances.

Lockheed Martin Ventures, the investment arm of the aerospace and defense contractor, is an investor in Venus Aerospace.

"Lockheed Martin is focused on rapidly delivering advanced capabilities that strengthen deterrence and provide decisive advantages for the warfighter," Tim Cahill, president, Lockheed Martin Missiles and Fire Control, said in a news release. "Our collaboration with Venus Aerospace allows us to evaluate a promising propulsion technology and determine how it can be integrated into future precision fires solutions. Efforts like this help accelerate innovation, reduce risk and shorten the path from emerging technology to operational capability."

Venus' RDRE is expected to enable vehicles to travel four to six times the speed of sound from a conventional runway and is about 15 percent more efficient than traditional alternatives, according to the company.

Venus says the reusable, affordable and scalable RDRE is designed with a "common propulsion architecture" that can work for multiple industries and mission types. The company has previously estimated that the hypersonic market is projected to surpass $12 billion by 2030.

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