The 10-county Houston metro added 126,720 residents from July 1, 2024, to July 1, 2025. Photo via Getty Images

Imagine that the Houston metro area swallowed a city the size of Pearland in just one year. That’s essentially what happened from 2024 to 2025, with the Houston metro ranking first in the U.S. for population growth based on the number of people.

New estimates from the U.S. Census Bureau show the 10-county Houston metro added 126,720 residents from July 1, 2024, to July 1, 2025. That’s just shy of Pearland’s roughly 133,000-resident tally.

To calculate population, the Census Bureau counts births, deaths, new residents, and moved-away residents.

Region’s population approaches 8 million

On July 1, 2025, the Houston metro’s population hovered slightly above 7.9 million, up 1.6 percent from the same time in 2024. In the very near future, the region’s population should break the eight million mark.

This follows massive growth in the past 20 years. From 2005 to 2025, the region’s population soared by 39 percent. By comparison, the growth rate from 2021 to 2025 sat at nine percent.

A forecast from the Texas Demographics Center indicates that under a middle-of-the-road scenario, the Houston metro’s population will reach nearly 8.5 million in mid-2030 and more than 9.5 million in mid-2040.

Dan Potter, director of Rice University’s Houston Population Research Center, attributes much of the region’s population surge to people moving to the area from outside the U.S. In Harris County, this means a combination of military personnel returning home, people living or working overseas coming back to the U.S., and immigrants relocating to the U.S., he tells CultureMap.

But Harris County fell short from 2024 to 2025 when it comes to people moving here from elsewhere in the U.S., according to Potter. Counties surrounding Harris County benefited from that trend, drawing new residents who preferred to settle in the suburbs.

“The incredible pull and attraction of the Houston area is its economy, its people, and its affordability, and the significant growth that was observed in 2024 and again in 2025 speaks to the magnetism of the region,” Potter says. “That pull to Houston is too strong to be turned off overnight.”

Cooling economy and immigration shifts slow down growth

Whether looking at urban or suburban places, population growth in the Houston area slowed in 2025 and appears to be slowing even more this year, Potter says.

“A cooling economy and changes to immigration policy are a one-two combination that could knock out the region’s population growth,” says Potter, citing the region’s addition of a less-than-expected 14,800 jobs in 2025 as an example.

Weaker population growth may not be felt evenly across the metro area, according to Potter.

A continuing influx of people from Houston to outlying counties such as Brazoria, Fort Bend, Liberty, Montgomery, and Waller could curb growth in Harris County, Potter said. Why? If the number of people arriving from other other countries flattens or even drops, then there could be “doughnut-style population growth for the next few years, where Harris County and Houston see declines while the suburban counties see an increase.”

Harris County represents 40 percent of region’s population lift

Houston-anchored Harris County accounted for almost 40 percent of the region’s population spike from 2024 to 2025. In one year, Harris County grew by 48,695 residents, or 1 percent, pushing its population past five million. That increase put Harris County in first place for numeric growth (rather than percentage growth) among all U.S. counties.

From 2020 to 2025, Harris County’s growth rate was 6.6 percent. It remains the country’s third largest county based on population, behind Southern California’s Los Angeles County and Illinois’ Chicago-anchored Cook County.

Harris County is on track to surpass Cook County in size in the near future. As of July 1, 2025, a nearly 150,000-resident gap separated population-losing Cook County and fast-growing Harris County.

The Texas Demographics Center predicts Harris County’s population will be 5.37 million in mid-2030 and just short of six million in mid-2040.

Suburban counties see significant population gains

Harris County isn’t the only county in the area that experienced a growth spurt from 2024 to 2025:

  • Waller County’s population climbed 5.69 percent, winding up at 69,858. Its growth rate ranked second among U.S. counties.
  • Liberty County’s population rose 4.4 percent to 121,364, putting its growth rate in eighth place among U.S. counties.
  • Montgomery County gained 30,011 residents, with its population landing at 781,194. That placed it at No. 4 among U.S. counties for numeric growth.
  • Fort Bend County picked up 24,163 residents, arriving at a total of 975,191 and positioning it at No. 8 among U.S. counties for numeric growth. Fort Bend County, the region’s second largest county based on population, is projected to break the one million-resident mark by July 2030, according to the Texas Demographics Center.

“Lower mortgage rates from 2009 to 2022 and the rise of remote work have made suburban housing more attractive, especially for families seeking affordability,” Pramod Sambidi, the Houston-Galveston Area Council’s assistant director of data analytics and research, said last year. “Additionally, suburban areas are seeing more multifamily developments than before the pandemic.”

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This article originally appeared on CultureMap.com.

Only Dallas surpasses Houston for retail construction right now. Getty Images

Houston booms as No. 2 U.S. market for retail construction in 2025

Construction Zone

Get ready for a gigantic cartload of new shopping opportunities in Houston. A new report indicates the equivalent of 21 Walmart supercenters is under construction in the region.

The report, published by commercial real estate services provider Lee & Associates, says Houston has nearly 3.9 million square feet of retail space under construction, making it the second most active market for new retail space in the U.S.

To put that in perspective, given the average Walmart supercenter measures 182,000 square feet, the 3.9 million-square-foot total would work out to 21 new supercenters being built in the region.

Dallas-Fort Worth is by far the most active U.S. market for new retail space; DFW leads more than 60 U.S. retail markets with nearly 7.15 million square feet of space under construction. The amount of retail space going up in DFW represents 15 percent of all retail space under construction in the more than 60 U.S. markets tracked by Lee & Associates.

Houston and Austin aren’t too far behind Dallas-Fort Worth, though.

Third-ranked Austin area has more than 3.4 million square feet of retail space being built.

What’s behind the surge in retail construction across Texas? Population growth.

Data recently released by the U.S. Census Bureau shows Houston was the second-fastest-growing metro from 2023 to 2024. DFW was the country’s third-fastest-growing metro from 2023 to 2024, based on the number of new residents, and Austin landed at No. 13.

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This article originally appeared on CultureMap.com.

Houston gained 43,217 residents from July 2023 to July 2024. Photo via Getty Images

Houston boasts No. 2 biggest population gain in U.S., Census data shows

Boomtown

Houston saw the second-highest population increase in the United States in 2024, according to the U.S. Census Bureau.

The new population report revealed Houston gained 43,217 residents from July 2023 to July 2024, bringing the city's population to 2,390,125.

Houston hung on to its ranking as the fourth largest city in the country and joined 11 other Southern cities that saw the largest numeric population gains in 2024, the report added.

Elsewhere in Texas, Fort Worth is now home to more than 1 million residents, surpassing Austin as the 11th largest city in the U.S. Fort Worth had the fifth-highest numeric increase in population, adding 23,442 residents during that same time frame to bring the city's total population to 1,008,106 residents.

Dallas retained its No. 9 spot on the list of the 15 most populous cities in the U.S. The city gained more than 23,000 residents during the one-year period, bringing its population to 1,326,087 people in 2024.


Austin slipped two spots and now ranks as the 13th largest city after adding more than 13,000 residents to bring the Texas Capital's population to 993,588.

San Antonio gained 23,945 residents — the fourth-highest increase nationwide — and was the only other city besides Houston to have a higher numerical growth rate than Fort Worth during the one-year period.

Fastest-growing U.S. cities
Princeton, a North Texas suburb of Dallas, topped the charts as the No. 1 fastest-growing U.S. city in 2024. The Census Bureau says the city's population has more than doubled in the last five years to more than 37,000 residents.

Fulshear, 34 miles from downtown Houston, has continued its rapid expansion as the second-fastest growing city. The suburb grew nearly 27 percent since the previous year, and its population rose to 54,629 residents as of July 2024.

Five additional Texas cities made the list of fastest-growing U.S. cities:

  • Celina, near Dallas (No. 4) with 18.2 percent growth (51,661 total population)
  • Anna, near Dallas (No. 5) with 14.6 percent growth (31,986 total population)
  • Fate, near Dallas (No. 8) with 11.4 percent growth (27,467 total population)
  • Melissa, near Dallas (No. 11) with 10 percent growth (26,194 total population)
  • Hutto, near Austin (No. 13) with 9.4 percent growth (42,661 total population)

The Austin suburb of Georgetown's growth has continued to slow down since 2023, and it no longer appears in the list of fastest-growing cities. However, it did surpass 100,000 residents in 2024. San Angelo, a small city in West Texas, also surpassed the 100,000-population threshold.

Most populous U.S. cities in 2024
New York City maintained its stronghold as the biggest in America in 2024, boasting a population of nearly 8.5 million residents. Los Angeles and Chicago also retained second and third place, with respective populations of nearly 3.88 million and more than 2.7 million residents.

"Cities in the Northeast that had experienced population declines in 2023 are now experiencing significant population growth, on average," said Crystal Delbé, a statistician in the Census Bureau’s Population Division. "In fact, cities of all sizes, in all regions, showed faster growth and larger gains than in 2023, except for small cities in the South, whose average population growth rate remained the same."

The 15 populous U.S. cities as of July 1, 2024 were:

  • No. 1 – New York, New York (8.48 million)
  • No. 2 – Los Angeles, California (3.88 million)
  • No. 3 – Chicago, Illinois (2.72 million)
  • No. 4 – Houston, Texas (2.39 million)
  • No. 5 – Phoenix, Arizona (1.67 million)
  • No. 6 – Philadelphia, Pennsylvania (1.57 million)
  • No. 7 – San Antonio, Texas (1.53 million)
  • No. 8 – San Diego, California (1.4 million)
  • No. 9 – Dallas, Texas (1.33 million)
  • No. 10 – Jacksonville, Florida (1 million)
  • No. 11 – Fort Worth, Texas (1 million)
  • No. 12 – San Jose, California (997,368)
  • No. 13 – Austin, Texas (993,588)
  • No. 14 – Charlotte, North Carolina (943,476)
  • No. 15 – Columbus, Ohio (933,263)
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A version of this article originally appeared on CultureMap.com.

Fulshear is growing faster than any other wealthy suburb. Photo courtesy of City of Fulshear/Facebook

This Houston neighbor was the fastest growing U.S. city in last decade

Booming Burb

It's no secret that Houston's population is growing faster than most other metros in the U.S., but now a surprising Houston-area neighbor has been named the No. 1 fastest-growing suburb nationwide over the last decade: the booming city of Fulshear.

Fulshear led the nation with an astonishing 1,082 percent increase in population from 2014 to 2023, according to a recent growth study by marketplace platform StorageCafe.

Overall, Texas cities dominated StorageCafe's list of the top 10 fastest-growing U.S. cities from 2014 to 2023.

The report said the city had nearly 27,000 residents in 2023, but now the U.S. Census Bureau estimates Fulshear's population has now grown to more than 42,600 people.

"With its blend of a relaxed lifestyle, urban conveniences, top-rated schools and strong job opportunities, Fulshear consistently ranks among the best places to live in Texas," the report's author wrote.

This isn't the first time Fulshear has entered the spotlight for its exploding population: it was the No. 2 fastest-growing U.S. city in 2023, and recently came out on top of GoBankingRates' new study ranking of the fastest-growing affluent suburbs in America for 2025.

Several other Houston-area suburbs also saw major growth over the last decade, including Manvel (No. 24), Katy (No. 82), and Conroe (No. 83).

"Manvel doubled its population between 2014 and 2023, while Katy and Conroe each recorded increases of over 50 percent," the report said. "By contrast, Houston itself grew by just 6 percent, aligning with the average growth rate for large U.S. cities."

The report added that the Houston area's population surge has also led to a high demand for housing, where home values have risen 60 percent over the last 10 years. Home prices in Fulshear stood at more than $521,000 in November 2024, whereas Manvel's home prices were over $431,000 during that same period.

For comparison, the national average price of a home is $354,000.

Katy and Conroe had the most affordable home prices out of the four Houston suburbs in the report, at $347,740 and $318,952, respectively, for November.

StorageCafe says the reasons for population shifts vary greatly, with many people seeking out cities with a more affordable cost of living, or those moving for socioeconomic factors like better employment opportunities.

"Population growth is far from even across the U.S. Some cities are experiencing significant increases, directly driven by steady in-migration, rising immigration and birth rates outpacing death rates," the report said. "But what’s fueling these trends runs deeper — economic and social forces like shifting job markets, the rise of remote and hybrid work and soaring living costs are all reshaping where people choose to live."

Other fast-growing Texas cities
Texas had the greatest number of cities to earn spots in the report's ranking of the 100 fastest-growing U.S. cities over the last decade, with 25 total cities making the cut with the highest growth rates nationwide.

Dallas-Fort Worth had the highest number of fastest-growing Texas suburbs on the list, comprising 11 cities: Celina (No. 2), Melissa (No. 3), Princeton (No. 7), Prosper (No. 8), Fate (No. 9), Anna (No. 14), Midlothian (No. 33), Royse City (No. 43), Forney (No. 45), Little Elm (No. 58), and Frisco (No. 72).

Meanwhile, Austin had five suburbs land on the list: Manor (No. 6), Leander (No. 16), Kyle (No. 53), Hutto (No. 54), and Buda (No. 68).

San Antonio also had five suburbs make the top 100, including Boerne (No. 63), Selma (No. 74), Fair Oaks Ranch (No. 70), New Braunfels (No. 77), and Canyon Lake (No. 99).

The top 10 fastest-growing cities over the last decade are:

  • No. 1 – Fulshear, Texas
  • No. 2 – Woodbridge, Virginia
  • No. 3 – Celina, Texas
  • No. 4 – Davenport, Florida
  • No. 5 – Melissa, Texas
  • No. 6 – Manor, Texas
  • No. 7 – Princeton, Texas
  • No. 8 – Prosper, Texas
  • No. 9 – Fate, Texas
  • No. 10 – Nolensville, Tennessee
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This article originally appeared on our sister site, CultureMap.com.

Harris County now boasts a population of more than 5 million. Photo via Getty Images

Harris County booms with 3rd biggest population in U.S.

Boomtown

Newly released U.S. Census Bureau data has revealed Harris County became the third most populous county nationwide in 2024, and it had the highest year-over-year growth rate from 2023.

The new population report, published this month, estimated year-over-year population data from 2023 to 2024 across all 3,144 U.S. counties, and 387 metro areas.

Harris County's numeric growth rate outpaced all other U.S. counties from July 1, 2023 to July 1, 2024, the report found. The Census Bureau estimated Harris County's population grew by 105,852 people year-over-year, bringing the total population to 5,009,302 residents. That's around a 2.16 percent growth rate.

Los Angeles County, California (No. 1) and Illinois' Cook County (No. 2) are the only two U.S. counties that have larger populations than Harris County. Los Angeles County now boasts a population of nearly 9.76 million, while Cook County's has increased to more than 5.18 million people.

The top 10 most populous counties in the U.S. are:

  • No. 1 – Los Angles County, California
  • No. 2 – Cook County, Illinois
  • No. 3 – Harris County, Texas
  • No. 4 – Maricopa County, Arizona
  • No. 5 – San Diego County, California
  • No. 6 – Orange County, California
  • No. 7 – Miami-Dade County, Florida
  • No. 8 – Dallas County, Texas
  • No. 9 – Kings County, New York
  • No. 10 – Riverside County, California

Montgomery County also ranked among the top 10 U.S. counties with the highest numeric growth, ranking 9th nationally after gaining 34,268 residents from 2023 to 2024. Montgomery County's population has now grown to 749,613 people.

In the report's national comparison of counties with the largest population growth by percentage, Montgomery County ranked No. 7 with a year-over-year growth rate of 4.8 percent.

Most populated U.S. metro areas

The U.S. Census Bureau additionally found Houston-Pasadena-The Woodlands nearly led the nation as the second-fastest growing metro area in 2024.

From July 2023 to July 2024, the Houston metro added 198,171 residents to bring the total population to 7,796,182.

New York-Newark-Jersey City was the only metro area to outpace Houston's growth during the one-year period. The New York-New Jersey metro added 213,403 new residents, which brought the total population to over 19.94 million last year.

Kristie Wilder, a Census Bureau Population Division demographer, said in the report that the nation's population growth in its major metros was largely impacted by international migration rather than changes in birth rates.

"While births continue to contribute to overall growth, rising net international migration is offsetting the ongoing net domestic outmigration we see in many of these areas," Wilder said.

Dallas-Fort Worth-Arlington was right behind Houston as the third-fastest growing U.S. metro in 2024. The Metroplex gained 177,922 residents last year, and now has a total population of more than 8.34 million.

The top 10 U.S. metros with the highest numeric growth from 2023 to 2024 are:

  • No. 1 – New York-Newark-Jersey City, New York-New Jersey
  • No. 2 – Houston-Pasadena-The Woodlands, Texas
  • No. 3 – Dallas-Fort Worth-Arlington, Texas
  • No. 4 – Miami-Fort Lauderdale-West Palm Beach, Florida
  • No. 5 – Washington-Arlington-Alexandria, D.C.-Virginia-Maryland-West Virginia
  • No. 6 – Phoenix-Mesa-Chandler, Arizona
  • No. 7 – Orlando-Kissimmee-Sanford, Florida
  • No. 8 – Atlanta-Sandy Springs-Roswell, Georgia
  • No. 9 – Chicago-Naperville-Elgin, Illinois-Indiana
  • No. 10 – Seattle-Tacoma-Bellevue, Washington
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This article originally appeared on our sister site, CultureMap.com.

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Houston brain health co. secures $6.5M for rare disease study

neuro funding

Houston-based Goldenrod Therapeutics, part of Fannin Partners' portfolio, has announced the initial close of a $6.5 million series seed preferred stock round.

The round was led by Ataxia Ventures and an affiliate of Fannin, according to a news release.

Goldenrod Therapeutics plans to use the funding to support manufacturing, formulation optimization, IND-enabling studies and a Phase I study of its drug to treat brain inflammation, known as 11h.

The study will consider how 11h, which blocks the enzyme PDE4, could treat Friedreich’s ataxia (FA), a rare genetic disease that affects movement, speech and balance. To date, other PDE4 inhibitors have proven to regulate neuroinflammation and neuronal signaling, but have had adverse gastrointestinal side effects or have not reached enough of the central nervous system, according to Goldenrod.

The company says its 11h is expected to have "broad applicability" with limited emetric side effects.

“Our 11h program is a next-generation, orally bioavailable, brain-penetrant PDE4 inhibitor, where researchers overcame longstanding limitations associated with earlier PDE4 inhibitors," Dr. Dev Chatterjee, CEO of Goldenrod, said in the news release. "We believe this creates the potential for a best-in-class therapy for Friedreich’s Ataxia and a potential foundation for development across multiple neurodegenerative and neuroinflammatory disorders.”

11h was first developed at the University of Nebraska Medical Center (UNeMed). Houston-based Fannin Partners in-licensed the product 2020 and landed SBIR Phase I funding to support its initial development for opioid use disorder soon after.

Goldenrod has also received funding to study 11h's effectiveness for multiple sclerosis, methamphetamine addiction and cocaine addiction.

Goldenrod says it is developing 11h to target a variety of neurological and inflammatory conditions, including Alzheimer's disease, multiple sclerosis, ALS, substance use disorders, Batten disease, pain and traumatic brain injury.

27 Houston companies make Fortune 500 for 2026, led by energy giants

Houston HQs

Houston is a giant among U.S. hubs for corporate headquarters.

The 2026 Fortune 500 lists 27 companies based in the Houston area, with many energy companies claiming top spots. Houston ties with Chicago for the second-most Fortune 500 headquarters, preceded only by New York City (53). Dallas-Fort Worth is home to 23 Fortune 500 headquarters.

Texas leads the nation for Fortune 500 headquarters (57), with California in the No. 2 spot and New York at No. 3.

“Texas is the undisputed headquarters of headquarters,” Gov. Greg Abbott said in a news release. “The world’s leading businesses invest with confidence in Texas because of our welcoming business climate, predictable regulatory environment, and skilled and growing workforce. People and businesses are choosing Texas because Texas works.”

The 2026 Fortune 500 ranks the largest U.S. corporations based on revenue in fiscal year 2025.

Here’s a rundown of the 27 Fortune 500 companies based in the Houston area.

  • No. 9 ExxonMobil
  • No. 21 Chevron
  • No. 29 Phillips 66
  • No.55 Sysco
  • No. 75 ConocoPhillips
  • No. 89 Enterprise Products Partners
  • No. 103 Plains GP Holdings
  • No. 133 Hewlett Packard Enterprise
  • No. 149 NRG Energy
  • No. 157 Quanta Services
  • No. 164 Baker Hughes
  • No. 173 Occidental Petroleum
  • No. 179 Waste Management
  • No. 201 EOG Resources
  • No. 204 Group 1 Automotive
  • No. 207 Halliburton
  • No. 223 Cheniere Energy
  • No. 236 Corebridge Financial
  • No. 262 Targa Resources
  • No. 266 Kinder Morgan
  • No. 388 Westlake
  • No. 435 CenterPoint Energy
  • No. 438 APA
  • No. 440 Comfort Systems USA
  • No. 455 NOV
  • No. 488 KBR
  • No. 496 Coterra Energy. Oklahoma City, Oklahoma-based Devon Energy and Houston-based Coterra Energy merged in early May, with the combined company retaining the Devon Energy name and the Houston headquarters.

The Greater Houston Partnership notes the Houston area soon will welcome its 28th Fortune 500 company. Expand Energy (formerly Chesapeake Energy), appearing at No. 362 on the 2026 list, says it’s moving its headquarters from Oklahoma City to Spring this year.

As the natural gas producer prepares to relocate to Texas, it’s hunting for a new leader. Nick Dell’Osso stepped down as president and CEO earlier this year. Board Chairman Michael Wichterich is interim president and CEO.

Dell’Osso became president and CEO of Oklahoma City-based Gulfport Energy effective May 28.

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This article first appeared on EnergyCapitalHTX.com.

Elon Musk's SpaceX is about to make its debut on Wall Street

Money Moves

Elon Musk's rocket company SpaceX will make its debut on Wall Street Friday, June 12, and both institutional and retail investors are expected to gobble up the 555.6 million shares going up for sale at $135 apiece. Musk, already the world's richest man, could become its first trillionaire.

SpaceX is likely to become the biggest IPO ever, with proceeds of around $75 billion. SpaceX hopes to become the first company to send people to Mars. In fact, part of Musk’s future compensation depends on SpaceX eventually establishing a colony of at least 1 million people on the red planet.

Why SpaceX is going public now

In a video conference on Musk's social media platform X, he told JPMorgan CEO Jamie Dimon that people have suggested for the last 10 years that he take SpaceX public. He's doing it now because the company plans to put 100,000 next-generation Starlink satellites into orbit. Deploying AI data centers in space is a “massive new growth base and you need capital for that,” he said.

Going public provides access to the capital that SpaceX needs. But it also exposes it to more scrutiny from shareholders and more regulatory oversight. That includes filing quarterly financial reports, which critics say incentivizes short-term thinking over longer-term planning and creates unnecessary costs for a company. Securities regulators are currently soliciting public comment on a proposal to require public companies to file the financial reports only twice every year.

How the IPO impacts the company

Musk will hold the majority of a special class of shares, giving him control over decisions related to company strategy, finances and personnel. On the latter, because of his ownership of most of these Class B shares, the only person who can fire Musk as CEO is Musk.

The company credits Musk with being the “driving force” behind its growth, innovation and success. But what happens if Musk is no longer in the picture? SpaceX warns that the loss of Musk could disrupt its ability to execute its strategy as well as hurt its “reputation and relationships with customers, partners and other stakeholders.”

The company also warns that finding a replacement with the same skills and experience as Musk would be time-consuming, if not nearly impossible. As Wedbush Securities analyst Dan Ives wrote Wednesday, “At the end of the day Musk is SpaceX and SpaceX is Musk.”

What could make or break SpaceX

Currently in the test phase, the gigantic reusable Starship rocket is key to SpaceX realizing Musk's ambitions. Much of the commercial space business hinges on SpaceX developing Starship’s capability to be fully reusable and hearty enough for a quick turnaround between flights. If that doesn't happen, SpaceX warns that putting data centers and satellites in space will take longer and cost more money, meaning it risks customers bailing on the company.

Analysts say that by pioneering reusable rockets, SpaceX has established a clear lead on competitors such as Blue Origin, led by Amazon founder Jeff Bezos. The Starlink satellite business competes with, among others, AST SpaceMobile – which is relying on a SpaceX rocket to send its latest generation of satellites into orbit next week.

The prospectus filed last week says SpaceX’s biggest potential market is the sale of business-oriented artificial intelligence products designed to transform how people get work done. It’s an opportunity SpaceX predicts would be worth $22.7 trillion if it could somehow dominate rivals like Anthropic, OpenAI and Microsoft in a highly competitive industry. But the prospectus shows no clear path to profitability for the xAI business, which merged with SpaceX earlier this year.

Why Wall Street is paying attention

If the SpaceX IPO is as successful, the stock could quickly join the Nasdaq 100, a widely followed index that tracks the 100 largest non-financial companies in the composite. That's important because some popular funds, such as the $460 billion QQQ exchange-traded fund, mimic the index and will automatically buy whatever is listed in the index.

Nasdaq recently changed its rules to allow select companies to enter the Nasdaq 100 after just 15 trading days.

S&P Dow Jones Indices, on the other hand, is sticking to established and more traditional thresholds that will not allow SpaceX or other companies with gargantuan IPOs faster entry into its S&P 500 index. That means even high-profile companies will still need to wait for their stocks to trade a full 12 months before they can enter the index.

Companies want to be in the S&P 500 in particular because it's arguably the most important index on Wall Street, with trillions of dollars either mimicking it exactly or benchmarked against it. Vanguard's VOO fund that tracks the S&P 500 has roughly $950 billion invested in it, for example.