Ranking It

Co-founder of Houston hypersonic engine co. lands on Inc. 500 list

Sassie Duggleby is on Inc.'s Female Founders 500 list for 2025. Courtesy photo

Five Houston female founders have been recognized by Inc. Magazine for their innovation, including Sassie Duggleby, the CEO and co-founder of groundbreaking space tech and engine company Venus Aerospace.

The women were named to Inc.'s Female Founders 500 list, which features female entrepreneurs based in the U.S. The group attracted approximately $9 billion in 2024 revenue and $10.6 billion in funding, according to Inc.

“Female founders know what struggle is, but they’re also experts of improvisation, adaptability, and creativity. The women featured on this year’s list exemplify these qualities," Diana Ransom, Inc. executive editor said in a release. "Through times of uncertainty, their unwavering dedication and steadfast leadership are not only inspiring but vital to driving progress.”

Venus Aerospace is the Houston-based company that is developing reusable hypersonic technology that it hopes "will revolutionize and redefine the boundaries of aviation, defense, and beyond." The company won the in the Deep Tech Business category in the 2024 Houston Innovation Awards. Duggleby also serves on the Texas Space Commission board of directors.

Duggleby is joined by four other Houston founders:

  • Stephanie Murphy, CEO and executive chairman of Aegis Aerospace, which provides space services, spaceflight product development, and engineering services. Murphy also serves on the Texas Aerospace Research and Space Economy Consortium Executive Committee.
  • Emily Cisek, founder of The Postage, now known as Paige, a comprehensive life planning and succession software platform for families and small businesses. The company won the Female-Owned Business category in the 2023 Houston Innovation Awards.
  • Margo Jordan, founder of adolescent mental health startup Enrichly, which uses AI-driven self-esteem development and behavioral insights to boost student performance.
  • Nina Magon, founder of Nina Magon Studio / Nina Magon Consumer Products, a residential and commercial interior design company.
"While I don't know many of the ladies on this list, I do know they're some of the most tenacious role models in entrepreneurship. I'm beyond honored to be included among them," Duggleby said in a LinkedIn post.
Twenty-eight Texas female founders made this list, including Kendra Scott and Allison Ellsworth, co-founder of Poppi, and many others.

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A version of this story first appeared on our sister site, InnovationMap.com.

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A View From HETI

Fervo Energy climbed 10 spots on Time's list of the World's Top GreenTech Companies of 2026. Photo via Fervo Energy

Six Houston-area businesses appear on Time magazine’s 2026 list of the world’s top greentech companies, with a high-flying name leading the pack.

The highest-ranked local company is Houston-based geothermal power producer Fervo Energy, which claims the No. 4 spot—up from No. 14 last year.

In May, Fervo raised nearly $1.9 billion in its IPO, making it the biggest-ever IPO in the clean energy sector. The company’s valuation now exceeds $10 billion.

Founded in 2017, Fervo borrows methods from the oil and gas sector to drill wells that go down vertically into hot rock before turning horizontal, letting water circulate through them and produce electricity from the heat it absorbs. Cape Station in Utah, the company's first utility-scale project, is set to start delivering power to the grid later this year, with capacity expected to grow to 100 megawatts by 2027.

Co-founder and CEO Tim Latimer tells Fast Company, which named him a 2026 Visionary of the Year, that he launched his career as a drilling engineer for fossil fuels, “but quickly became obsessed with this idea that the drilling techniques we were using would actually be transformative for the world of geothermal as well.”

Fast Company notes the geothermal power generated by Cape Station will be available 24/7, unlike wind and solar power.

“When you start adding something to the grid mix that’s affordable and works around the clock,” Latimer says, “that’s going to be a huge asset to meeting our country’s energy needs.”

Time teamed up with data provider Statista to compile the second annual ranking of the 250 top greentech companies in the world. Companies on the list either develop or provide green technology, products, or services that help ease or reverse the environmental impacts of human activity.

Statista gathered and analyzed data from more than 8,300 companies to create the list, and they were scored in three categories: positive environmental impact, innovation, and financial strength. Fervo earned a score of 94.63 out of 100.

Joining Fervo on this year’s list are:

  • Houston-based Quaise Energy (No. 78), which specializes in terawatt-scale geothermal power
  • The Woodlands-based Plus Power (No. 112), which develops, owns and operates battery storage projects
  • Houston-based Utility Global (No. 167), which develops decarbonization technology
  • Houston-based 1PointFive (No. 217), an Occidental Petroleum subsidiary that offers large-scale carbon removal and storage.
  • Houston-based Sage Geosystems (No. 250), which produces commercial-scale geothermal power

Earlier this year, six Houston-area companies landed on Time's list of top greentech companies in America: Fervo (No. 1), Quaise Energy (No. 49), Plus Power (No. 71), Utility Global (No. 98), Solugen (No. 199) and Noodoe (No. 215).

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