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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Tech giant Apple doubles down on Houston with new production facility

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Tech giant Apple announced that it will double the size of its Houston manufacturing footprint as it brings production of its Mac mini to the U.S. for the first time.

The company plans to begin production of its compact desktop computer at a new factory at Apple’s Houston manufacturing site later this year. The move is expected to create thousands of jobs in the Houston area, according to Apple.

Last year, the Cupertino, California-based company announced it would open a 250,000-square-foot factory to produce servers for its data centers in the Houston area. The facility was originally slated to open in 2026, but Apple reports it began production ahead of schedule in 2025.

The addition of the Mac mini operations at the site will bring the footprint to about 500,000 square feet, the Houston Chronicle reports. The New York Times previously reported that Taiwanese electronics manufacturer Foxconn would be involved in the Houston factory.

Apple also announced plans to open a 20,000-square-foot Advanced Manufacturing Center in Houston later this year. The project is currently under construction and will "provide hands-on training in advanced manufacturing techniques to students, supplier employees, and American businesses of all sizes," according to the announcement. Apple opened a similar Apple Manufacturing Academy in Detroit last year.

Apple doubles down on Houston with new production facility, training center Photo courtesy Apple.

“Apple is deeply committed to the future of American manufacturing, and we’re proud to significantly expand our footprint in Houston with the production of Mac mini starting later this year,” Tim Cook, Apple’s CEO, said in the news release. “We began shipping advanced AI servers from Houston ahead of schedule, and we’re excited to accelerate that work even further.”

Apple's Houston expansion is part of a $600 billion commitment the company made to the U.S. in 2025.

Houston energy trailblazer Fervo taps into hottest reservoir to date

Heating Up

Things are heating up at Houston-based geothermal power company Fervo Energy.

Fervo recently drilled its hottest well so far at a new geothermal site in western Utah. Fewer than 11 days of drilling more than 11,000 feet deep at Project Blanford showed temperatures above 555 degrees Fahrenheit, which exceeds requirements for commercial viability. Fervo used proprietary AI-driven analytics for the test.

Hotter geothermal reservoirs produce more energy and improve what’s known as energy conversion efficiency, which is the ratio of useful energy output to total energy input.

“Fervo’s exploration strategy has always been underpinned by the seamless integration of cutting-edge data acquisition and advanced analytics,” Jack Norbeck, Fervo’s co-founder and chief technology officer, said in a news release. “This latest ultra-high temperature discovery highlights our team’s ability to detect and develop EGS sweet spots using AI-enhanced geophysical techniques.”

Fervo says an independent review confirms the site’s multigigawatt potential.

The company has increasingly tapped into hotter and hotter geothermal reservoirs, going from 365 degrees at Project Red to 400 degrees at Cape Station and now more than 555 degrees at Blanford.

The new site expands Fervo’s geologic footprint. The Blanford reservoir consists of sedimentary formations such as sandstones, claystones and carbonates, which can be drilled more easily and cost-effectively than more commonly targeted granite formations.

Fervo ranks among the top-funded startups in the Houston area. Since its founding in 2017, the company has raised about $1.5 billion. In January, Fervo filed for an IPO that would value the company at $2 billion to $3 billion, according to

Axios Pro.

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This article originally appeared on EnergyCapitalHTX.com.

11 Houston researchers named to Rice innovation cohort

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The Liu Idea Lab for Innovation and Entrepreneurship (Lilie) has named 11 students and researchers with breakthrough ideas to its 2026 Rice Innovation Fellows cohort.

The program, first launched in 2022, aims to support Rice Ph.D. students and postdocs in turning their research into real-world ventures. Participants receive $10,000 in translational research funding, co-working space and personalized mentorship.

The eleven 2026 Innovation Fellows are:

Ehsan Aalaei, Bioengineering, Ph.D. 2027

Professor Michael King Laboratory

Aalaei is developing new therapies to prevent the spread of cancer.

Matt Lee, Bioengineering, Ph.D. 2027

Professor Caleb Bashor Laboratory

Lee’s work uses AI to design the genetic instructions for more effective therapies.

Thomas Howlett, Bioengineering, Postdoctoral 2028

Professor Kelsey Swingle Laboratory

Howlett is developing a self-administered, nonhormonal treatment for heavy menstrual bleeding.

Jonathan Montes, Bioengineering, Ph.D. 2025

Professor Jessica Butts Laboratory

Montes and his team are developing a fast-acting, long-lasting nasal spray to relieve chronic and acute anxiety.

Siliang Li, BioSciences, Postdoctoral 2025

Professor Caroline Ajo-Franklin Laboratory

Li is developing noninvasive devices that can quickly monitor gut health signals.

Gina Pizzo, Statistics, Lecturer

Pizzo’s research uses data modeling to forecast crop performance and soil health.

Alex Sadamune, Bioengineering, Ph.D. 2027

Professor Chong Xie Laboratory

Sadamune is working to scale the production of high-precision neural implants.

Jaeho Shin, Chemistry, Postdoctoral 2027

Professor James M. Tour Laboratory

Shin is developing next-generation semiconductor and memory technologies to advance computing and AI.

Will Schmid, Electrical and Computer Engineering, Postdoctoral 2025

Professor Alessandro Alabastri Laboratory

Schmid is developing scalable technologies to recover critical minerals from high-salinity resources.

Khadija Zanna, Electrical and Computer Engineering, Ph.D. 2026

Professor Akane Sano Laboratory

Zanna is building machine learning tools to help companies deploy advanced AI in compliance with complex global regulations.

Ava Zoba, Materials Science and Nano Engineering, Ph.D. 2029

Professor Christina Tringides Laboratory

Zoba is designing implantable devices to improve the monitoring of brain function following tumor-removal surgery.

According to Rice, its Innovation Fellows have gone on to raise over $30 million and join top programs, including The Activate Fellowship, Chain Reaction Innovations Fellowship, the Texas Medical Center’s Cancer Therapeutics Accelerator and the Rice Biotech Launch Pad. Past participants include ventures like Helix Earth Technologies and HEXASpec.

“These fellows aren’t just advancing science — they’re building the future of industry here at Rice,” Kyle Judah, Lilie’s executive director, said in a news release. “Alongside their faculty members, they’re stepping into the uncertainty of turning research into real-world solutions. That commitment is rare, and it’s exactly why Lilie and Rice are proud to stand shoulder-to-shoulder with them and nurture their ambition to take on civilization-scale problems that truly matter.”