Here's what Houston company scored the No. 2 spot among the fastest-growing private companies in the Southwest. Photo via Getty Images

Revenue growth is on fire at Houston-based Simple Solar.

Revenue at Simple Solar, a provider of residential solar installations, soared 8,007 percent from 2019 to 2021, putting it at No. 2 among the fastest-growing private companies in the Southwest. It leads the list of 25 Houston-area companies appearing in the new Inc. 5000 Regional rankings for the Southwest.

Between 2019 and 2021, the 165 private companies on the Southwest list posted an average growth rate of 557 percent. In 2021 alone, they added 16,116 jobs and nearly $5.5 billion to the Southwest’s economy.

“This year’s Inc. 5000 Regional winners represent one of the most exceptional and exciting lists of America’s off-the-charts growth companies,” says Scott Omelianuk, editor-in-chief of Inc. magazine. “They’re disruptors and job creators, and all delivered an outsized impact on the economy. Remember their names and follow their lead. These are the companies you’ll be hearing about for years to come.”

Here are the 25 Houston-area companies that made the Inc. 5000 Regional list for the Southwest, including their regional rankings.

  • No. 2 Simple Solar, Houston-based provider of residential solar installations, 8,007 percent growth
  • No. 6 Medical Edge Recruitment, The Woodlands-based health care recruiting and staffing firm, 2,980 percent growth
  • No. 8 Specialty1 Partners, Houston-based provider of surgical support services for dental practices, 2,921 percent growth
  • No. 15 Magnolia-based online women’s clothing retailer Jess Lea, 1,471 percent growth
  • No. 36 Houston-based accounting and advisory firm EFS Group, 458 percent growth
  • No. 39 Blackbuck Resources, Houston-based designer, builder, and operator of water infrastructure for the oil and gas industry, 432 percent growth
  • No. 48 Leveled Concrete, Houston-based provider of concrete and foundation repair services, 298 percent growth
  • No. 52 iCRYO Brands, Houston-based franchisor of cryotherapy centers, 269 percent growth
  • No. 53 TAXA Outdoors, Houston-based retailer of camping trailers, 268 percent growth
  • No. 58 Proxima Clinical Research, Houston-based contract research organization, 243 percent growth
  • No. 64 Ledge, Katy-based seller of in-pool and backyard furniture and accessories, 234 percent growth
  • No. 66 TekRevol, Houston-based software developer, 226 percent growth
  • No. 79 Finish Line Tax Solutions, Houston-based tax relief firm, 194 percent growth
  • No. 82 Incfile, Houston-based provider of services for small businesses, 192 percent growth
  • No. 99 Flocknote, Magnolia-based provider of technology that helps churches boost attendance and foster connections, 152 percent growth
  • No. 125 Onit, Houston-based developer of workflow and AI software, 104 percent
  • No. 137 InterLinc Mortgage, Houston-based mortgage lender, 85 percent growth
  • No. 140 Classy Art, Houston-based supplier of wall décor, 83 percent growth
  • No. 145 Zulie Venture (Cellpay), Sugar Land-based provider of prepaid wireless services, 78 percent growth
  • No. 149 Total Pump Solutions, Houston-based distributor of fire suppression equipment, 75 percent growth
  • No. 155 Construction Concepts, Houston-based commercial construction firm, 67 percent growth
  • No. 157 Energy Ogre, Houston-based service that helps consumers find electricity plans, 63 percent growth
  • No. 164 Garrison Construction Group, Houston-based commercial construction firm, 60 percent growth
  • No. 165 Technocrats Domain, Houston-based provider of IT services, 60 percent growth
  • No. 166, G&A Partners, Houston-based professional employer organization, 60 percent growth
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Experts: Houston's VC ecosystem has set the foundation — now we need scale

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Fervo Energy went public earlier this summer. The Houston geothermal company priced its IPO at $27 per share, raised $1.89 billion, and opened the next morning at a market capitalization north of $10 billion. By most measures, it is the largest venture-backed cleantech IPO in history and an unambiguous win for Houston. It’s also a useful moment to look at where Houston's venture ecosystem stands and where it can go. The highlight: Houston's venture ecosystem has real foundations and, with increased company formation activity, can grow into the scale our city's ambitions deserve.

A Houston energy story in the national recovery

The recent uptick in Houston venture activity follows national trends. U.S. venture deal count contracted roughly 22 percent from its 2021 peak through 2024 before rebounding to about 16,700 rounds in 2025. Houston's 23 percent increase in VC funding from 2023 to 2024 is part of a national recovery of comparable magnitude over the same time window.

The energy sector is where Houston exhibits unique trends—and where the story turns clearly positive. (Houston's strong health and space sectors deserve their own separate consideration.) By deal count, energy-related rounds have accounted for 15 to 20 percent of Houston activity, roughly consistent over the past few years.

By capital, energy's share surged from about 14 percent in 2023 to over 60 percent in 2025, driven by a small number of large Houston-headquartered rounds, primarily in geothermal and related technologies. Fervo is the obvious anchor, but Sage Geosystems, Quaise Energy, Zeta Energy, Vaulted Deep, Applied Carbon and Mariana Minerals have all closed meaningful rounds. Houston is concentrated and accelerating as an energy capital market, an invaluable position to build upon.

From foundation to scale

The institutional pieces are in place. Greentown Labs, Activate, the Ion and others have built sector-specialized infrastructure most cities would struggle to assemble. Fervo itself is an alum of both Activate and Greentown Labs. Mercury Fund closed its $160 million Fund V, its largest ever. Houston Angel Network, GOOSE Capital, Fathom Fund, and broader pre-seed and seed capital coverage are here. The Houston $10 million-plus Series A list now includes 40 rounds since 2021, which break roughly into two eras. While 2021 to 2022 was biotech-heavy, with companies like Sporos Bioventures, RadioMedix, Cellenkos and Coya Therapeutics, 2024 to 2025 has tilted clearly toward energy, climate, and critical minerals, with Vaulted Deep, Applied Carbon, Mariana Minerals, Sage Geosystems and Ignis H2 Energy among them.

What’s less developed is the volume of seed-stage companies flowing into that capital. Imagine a dozen more Fervos coming out of that infrastructure over the next decade, each generating jobs, recycled founder capital, and the next wave of operators and angel investors. That is the kind of opportunity Houston has within reach if we build the company-formation pipeline to feed it. To be relevant on the national stage as a venture market, and to drive an economy the size of Houston's into the 2030s, the city needs to be doing closer to 20 Series A rounds per month rather than per year. That throughput implies roughly 1,000 seed rounds per year, feeding the funnel at a 20 percent to 30 percent graduation rate. Reaching such throughput depends on how many new founders Houston produces and how quickly our innovation ecosystem can help them achieve lift-off.

Houston in context

The comparative picture brings the scaling challenge into focus. Between 2021 and 2024, Houston-area startups closed between 126 and 153 disclosed venture rounds per year, against a national count between 9,854 and 14,125. That places Houston at a little over 1 percent of the U.S. deal count. For comparison, Austin ran about three times Houston's deal count each year.

At the Series A level, Houston closed between 12 and 24 rounds in any given year. The median Houston Series A across the period was about $10.7 million, compared with $15.4 million in San Francisco. Houston founders are raising fewer and smaller Series A rounds than founders in peer metros, which points directly to where Houston has the most room to grow.

The unicorn picture tells the same story. From 2021 through 2025, the U.S. produced 590 venture-backed unicorns. Four were Houston-based: Solugen and Axiom Space in 2021, Cart.com in 2023, and Fervo Energy in 2024. Adding HighRadius from 2020 brings Houston's all-time total to five. Austin added 19 over the same five-year window. The path from here is to make Houston's entries on lists like these less the exception and more the rule.

Where this leads

Houston has a real opportunity to become the deepest, most credible energy and climate capital market in the country, with the company formation, talent and operator density to support it. The data shows the foundation is already in place. Fervo, Solugen and the growing roster of energy-adjacent Series A graduates are proof. Fervo's IPO is the first of what should be many. Houston has not had a venture-backed cleantech liquidity event of this scale before, and the city now has one to reference, recruit against and build on. With increased company formation at the seed and pre-seed stages, a Fervo-scale outcome need not be a generational event in Houston, but instead, it can become part of a chain reaction powering the city's economy.

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Stephanie T. Schmidt, PhD, is a Venture Fellow at Energy Transition Ventures and an Executive MBA candidate at Rice University. Lawson Gow is the Chief Operating Officer of Greentown Labs. The full Houston VC landscape report is available at Energy Transition Ventures and CleanTech.org.

Sources: Crunchbase, PitchBook-NVCA, Carta

8 can't-miss Houston business and innovation events for July

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Editor's note: Summer is in full swing in Houston, but the city's innovation ecosystem isn't slowing down. This month brings AI workshops, energy and manufacturing discussions, entrepreneur-focused networking, and opportunities to connect with investors and industry leaders. Here’s what not to miss and how to register. Please note: this article may be updated to add more events.

July 7 — How Oil and Gas Professionals are Building Wealth Smarter

Hear from oil and gas professionals on how to preserve wealth at this event put on by Financial Advice Center. The conversation will touch on topics like investing, taxes and retirement planning.

This event is Tuesday, July 7, from noon-1 p.m. at the Ion. Register here.

July 7 — What AI, Cybersecurity, and Tequila Have in Common.

Join Blue People and Alpfa Houston for this engaging presentation on the advantages and risks associated with AI at the latest installment of Tech + Tequila Talk. Cybersecurity veteran Reynaldo Gonzalez will lead the conversation.

This event is Tuesday, July 7, from 5-7 p.m. at the Ion. Register here.

July 7 — Speed to Market: Houston’s Advanced Manufacturing Edge

The Greater Houston Partnership presents a forum that explores what allows advanced manufacturing projects in Houston to move from concept to operation, where delays and bottlenecks occur, and more. Industry leaders Jennifer Clement from CliftonLarsonAllen LLP and Sarah Janes from San Jacinto College will lead the discussion.

This event is Tuesday, July 7, from 11:30 a.m.-1 p.m. at the Partnership Tower. Register here.

July 9 — Capital Connections Summit

Houston City College Center for Entrepreneurship will host the Capital Connections Summit this month, with a panel discussion focused on access to capital and technical assistance for small businesses and entrepreneurs. The event will be moderated by the U.S. Small Business Administration Houston District Office and will feature lenders, nonprofit microlenders, business advisors, and entrepreneurial support organizations. A live Q&A will follow the panel.

This event is Thursday, July 9, from 11 a.m.-1:30 p.m. at Houston City College Central Campus. Register here.

July 9 — Upstream: Digital Tech Meetup at Second Draught

Join Timbergrove at this month's gathering of energy, operations and technology professionals from across the upstream ecosystem. Discuss challenges, explore new ideas and network over pizza and beer at Second Draught.

This event is Thursday, July 9, from 5:30–8 p.m. at the Ion. Register here.

July 14 — Why Networking Isn’t Turning Into Deals, And What To Do Instead

Jada Powell, founder of Powell Consulting Group, will break down why networking often fails to convert into deals and what companies can do differently to turn conversations into qualified opportunities. Powell works with oil and gas, energy, and industrial companies on business development solutions. This session is part of the monthly Pipeline Series: How Oil & Gas Companies Actually Grow Revenue.

This event is Tuesday, July 14, from noon-1 p.m. at the Ion. Register here.

July 15 — From Pilot to Performance: Building Your AI Procurement Roadmap

It's not too late to join in on the GHP's two-part AI series on moving from experimentation to implementation. In session two, explore how procurement and supply chain leaders can scale AI responsibly to create long-term business value. This event will be led by Cassye Cook Provost, founder and principal of RossGrigsby Consultancy.

This virtual event is Wednesday, July 15, from 8:30-10 a.m. Register here.

July 30 — Rice University Summer Engineering Innovation Program - Demo Day 2026

Meet the young minds and see the final team project presentations from Rice University’s Summer Engineering Innovation Program. The 10-week program challenges Rice students to solve real-world challenges using AI, digital engineering, model-based systems engineering and Industry 4.0 technologies.

This event is Thursday, July 30, from 6-8 p.m. at the Ion. Find more information here.