While no Houston business was able to break into the top 100, four did make the cut for this prestigious list. Photo via Getty Images

Four Houston businesses made the cut on Deloitte's recently unveiled list of the fastest-growing technology companies in North America — and two are energy tech companies.

For the 29th year, 2023 Technology Fast 500 ranked top tech, media, telecommunications, life sciences, and energy technology companies based on fiscal year revenue growth from 2019 to 2022. While no Houston business was able to break into the top 100, four did make the cut for this year's list.

“It is great to see Houston represented alongside established technology hubs on this year’s Fast 500 list,” Amy Chronis, vice chair, US Energy and Chemicals Leader and Houston managing partner at Deloitte, says in a statement. “Houston is planting seeds for future innovation, and the companies named to this year’s list confirm our city’s value proposition as an innovative community. We look forward to this growth continuing in the future and extend our congratulations to this year’s Houston winners.”

Houston's two energy representatives are NatGasHub.com, a pipeline data source, at No. 356 with 364 percent growth and P97 Networks, a fintech company for gas stations, at No. 506 with 225 percent growth.

The other two Houston businesses are digital media company Direct Digital Holdings at No. 108 with 1,325 percent growth and B2B software solutions business Liongard at No. 208 with 680 percent growth

Thirty Texas companies made the list of the 541 ranked, making it the fourth most concentrated hub on the list behind the Bay Area, Tri-State Area, and New England. The companies on the list reported a revenue growth ranging from 201 percent to 222,189 percent over the three-year time frame from 2019 to 2022. The average growth rate was 1,934 percent and a median growth rate of 497 percent.

“Each year, we look forward to reviewing the progress and innovations of our Technology Fast 500 winners," Paul Silverglate, vice chair, Deloitte LLP and U.S. technology sector leader, says in the release. "This year is especially celebratory as we expand the number of winners to better represent just how many companies are developing new ideas to progress our society and the world, especially during a slow economy. While software and services and life sciences continue to dominate the top 10, we are encouraged to see other categories making their mark."

Software dominated the industry breakdown with 57 percent of the companies working in that field. However, the top company for 2023 was Vir Biotechnology Inc., a life science company that developed a COVID-19 treatment. Vir was also the top company in 2022.

Last year, only one Houston company made the list. At No. 372 Onit reported a revenue increase of 369 percent. The company also made the 2021 list, along with Graylog and Enercross.

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Houston energy transition hub opens applications for new fundraising cohort

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EnergyTech Cypher has opened applications for its second Liftoff fundraising program.

Applications close May 20 for the 10-week virtual fundraising sprint. The program is geared toward energy and climatech founders preparing to raise their first institutional round. It will cover fundraising requisites, like pitch materials, term sheet negotiation and round closing, according to a release from EnergyTech Cypher.

The program kicks off June 1 and runs every Monday from 1-3 p.m. CST. It will conclude with an in-person capstone simulation in Houston on August 3, where founders will work to close a mock round.

Jason Ethier, EnergyTech Cypher founder and CEO, will lead the program with Payal Patel, an EnergyTech fellow and entrepreneur in residence.

The program is available through Cephyron, EnergyTech Cypher's new investor relationship management platform, built specifically for energy and climatech founders. Users must have a Cephyron Boost membership to participate in the Liftoff program.

The Cephyron IRM app recently went live and is available to founders at any point in their fundraising process, according to the news release. The platform aggregates investor data, tracks market signals and delivers curated weekly recommendations.

EnergyTech Cypher launched Liftoff last year. The inaugural cohort included 19 startups, including Houston-based AtmoSpark Technologies, The Woodlands-based Resollant and others. Each participant closed at least one fundraising deal, according to EnergyTech Cypher.

EnergyTech Cypher rebranded from EnergyTech Nexus earlier this year. It also launched its CoPilot accelerator in 2025. The inaugural group presented its first showcase during CERAWeek last month.

EnergyTech Cypher's annual Pilotathon Pilot Pitch and Showcase applications also opened this month. Find more information here.

Houston climatech startup raises $29M funding round​

fresh funding

Houston-based NanoTech Materials has closed a $29.4 million Series A.

The round was led by Austin-based HPI Real Estate & Investments. Houston-based Goose Capital and Austin-based Milliken & Company also participated.

Nanotech has developed its patented Insulative Ceramic Particle (ICP) technology, which reduces heat transfer in buildings and outdoor infrastructure, improving efficiency and safety. It's known for its Cool Roof Coat, Wildfire Shield and Insulative Coat: Cool Touch product lines.

With the new funding, Nanotech plans to scale operations and expand its market reach for its products.

“We’re addressing one of the pressing and urgent challenges facing infrastructure owners today: controlling energy costs and extending asset life,” Mike Francis, CEO and co-founder of NanoTech Materials, said in a news release. “This financing marks a transformative moment for us. It allows us to rapidly scale production and bring our high-performance materials to market faster, while delivering measurable cost savings and redefining what resilience looks like in today’s built environment.”

Nanotech launched in 2020 and was the first company selected for Halliburton Labs. It moved into a 43,000-square-foot space in Katy in 2023. It brought on new partners that expanded the company's reach in the Middle East and Singapore the following year. Its technology was recognized as one of Time magazine's 200 Best Inventions of 2024.

“We were early investors in Nanotech Materials and are pleased to continue supporting the company as it becomes a leader in breakthrough materials science and technology,” John Chaney, investor at Goose Capital and board member at NanoTech, added in the release. “NanoTech’s ability to elevate fire resilience and energy efficiency in the built environment is critical for strengthening and hardening infrastructure. Its pioneered approach is transforming current building standards and making our lives safer.”

The company has secured $34.4 million in total to date, according to the release. It raised an oversubscribed funding round in 2023 and a $5 million seed round in 2020.

Houston clean energy startup acquired by battery storage company FlexGen

m&a activity

A North Carolina company has acquired Houston-based Clean Energy Services, a provider of services for battery energy storage systems and utility-scale solar, for an undisclosed amount.

The buyer is Durham, North Carolina-based FlexGen Power Systems, a provider of battery energy storage software and services.

Clean Energy Services (CES), whose offices are at the Ion, will operate as a subsidiary of FlexGen. Existing CES customers will continue to receive services from CES without disruption or change, FlexGen says.

“Demand for reliable, high-performance power is accelerating, and customers need partners who can deliver at scale,” Kelcy Pegler, CEO of FlexGen, said in a news release. “The addition of CES strengthens our service platform and reinforces our leadership in energy storage technology.”

Ahmad Atwan and Constantine Triantafyllides co-founded CES in 2022. As a startup, CES had raised $8 million in venture capital, according to PitchBook.

“CES has achieved a market leadership position in battery storage services by focusing on reliable speed of service delivery and optimizing asset performance,” Atwan, the company’s CEO, added the release. “FlexGen and CES have been strong partners for years, and this transaction enables us to deliver more robust solutions across a complementary set of customers and markets.”

CES will continue to operate its remote operations center in Houston for over 1 gigawatt of solar assets and 4.5 gigawatt-hours of battery assets, while FlexGen will maintain its remote operations center in Durham.