Inc. magazine has identified the fastest-growing companies in Houston. Nick Bee/Pexels

Bellaire-based startup Instafuel is pumping up its revenue in a big way.

Among the 250 fastest-growing companies in Texas identified by Inc. magazine, Instafuel tops the group of businesses based in the Houston metro area and ranks fifth statewide. Houston-based companies make up 68 of the state's fast-growing companies — eight Houston companies make up the top 25 list.

Instafuel, whose official corporate name is Fuel Husky LLC, provides mobile refueling services to B2B clients. The Inc. ranking, released March 13, shows Instafuel posted revenue growth of 1,353 percent from 2016 to 2018.

According to a November 2019 article published by CSP magazine, Instafuel has expanded to 30 trucks that have dispensed nearly 10 million gallons of fuel to more than 150 B2B clients in major Texas metro markets like Houston, Dallas-Fort Worth, and Austin. CSP covers the convenience and petroleum retailing industry.

"We've been bootstrapping … in stealth mode for the last four years, just trying to grow this business one [client] by one, trying to truly understand what it means to be a mobile refueler, or what we call a compact mobile refueler, and trying to target and understand the business model for small- to medium-sized business fleets," Nour Baki, vice president and co-founder of Instafuel, told the magazine.

Ranked second in the Houston area and sixth statewide by Inc. is Spring-based Bellatorum Resources LLC, whose revenue shot up 1,261 percent from 2016 to 2018. Bellatorum, a veteran-owned and veteran-operated investment company, specializes in mineral rights and oil royalty acquisitions.

"I think our work ethic and customer service is what makes us different from our competitors," Chris Bentley, president and CEO of Bellatorum Resources, told the Oil & Gas Council in July 2018.

"Based on the feedback I consistently receive from mineral owners, they tell me that many of our competitors fail to return phone calls and emails, and sometimes even fail to treat them with common courtesy and respect during their business dealings," Bentley added. "We believe in putting the mineral owner first, which always pays off for us."

At No. 3 in the Houston area and No. 8 statewide is Houston-based Sarvicus LLC. Sarvicus, an IT services and utilities provider, grew revenue by 1,048 percent from 2016 to 2018.

"Whether it's a process, piece of equipment, or a tool, we try to optimize its efficiency. When we are successful, that often translates to benefits for our customers," Sarvicus co-founder and CEO Marc Packard told CIOReview magazine.

Houston-based SIA Solutions LLC appears at No. 4 among Houston-area companies and No. 9 among Texas companies. From 2016 to 2018, revenue at the professional services engineering and consulting firm soared 1,030 percent.

"Because of our client-first philosophy, we're willing to take on tough challenges and deliver. It's in our culture. It's natural to us," CEO Srini Neralla told the McFerrin Center for Entrepreneurship at Texas A&M University's Mays Business School in November 2019. We put together strong teams comprising of firms our size or larger, including universities, in order to deliver what our clients want."

With a 2016-18 growth rate of 824 percent, Houston-based Zahroof Valves Inc. nails down the No. 5 spot among Houston-area companies and No. 14 among Texas companies. Zahroof Values makes and markets specialized valves for reciprocating gas compressors. Its investors include Saudi Aramco Energy Ventures LLC, the investment arm of oil giant Saudi Aramco.

In an August 2019 release, Zahroof Valves CEO Tony Gioffredi said: "Our commitment to driving positive change [in] the oil and gas industry is shown through our innovative products … ."

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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 the founder of a stealth startup, a Venture Fellow at Energy Transition Ventures, and an Executive MBA candidate at Rice University's Jones Graduate School of Business. 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.