Upcoming US IPOs to Watch in Late September
2026
Every September, a new crop of names starts showing up on the Nasdaq and NYSE, S-1 filings get passed around trading desks, and Wall Street starts talking up "the next big thing" all over again. If you've searched "US stock market news" or "top US stocks 2026" recently, odds are an IPO headline or two has already crossed your feed.
I'll be upfront: after covering a lot of these cycles, I've learned to approach them with equal parts curiosity and caution. Some IPOs turn into long-term compounders. Others pop on day one and quietly fade a year later. Avoiding IPOs entirely isn't really the answer — understanding what you're actually buying into before you tap "buy" on your brokerage app is.
So let's get into the calendar shaping up for late September 2026: what each company is bringing to market, and how a long-term investor might want to think about IPO investing more broadly.
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September 2026 US IPO Calendar at a Glance
This is the full lineup as of September 17, 2026, with pricing and status pulled from SEC filings and exchange data.
| Symbol | Company | Exchange | Price Range | Shares Offered | Deal Size | Status |
|---|---|---|---|---|---|---|
| HYACU | Haymaker Acquisition Corp V | NYSE | $10.00 | 25,000,000 | $250M | Already priced and trading (Sep 17) |
| ETRA | Electra Therapeutics, Inc. | NASDAQ | $14.00–$16.00 | 21,666,667 | ~$325M | Upcoming, Sep 18 |
| HNUC | Holtec Nuclear Corporation | NASDAQ | $15.00–$18.00 | 50,000,000 | ~$825M | Upcoming, Sep 18 |
| OIG | Orion180 Insurance Group Inc. | NASDAQ | $15.00–$17.00 | 20,000,000 | ~$320M | Upcoming, Sep 18 |
| AMRO | Amaero Inc. | NASDAQ | Pricing pending | 7,456,500 | ~$52.6M | Upcoming, pricing imminent |
| BMB | Bamboo Insurance Services, Inc. | NYSE | $18.00–$20.00 | 35,000,000 | ~$665M | Upcoming, Sep 23 |
| PTT | Siyata PTT | NASDAQ | $7.00 | 6,112,327 | ~$43M | Upcoming, Sep 30 |
Worth flagging: some of these figures have shifted since earlier reports, and that's normal for IPO terms right up until pricing night. Amaero's deal size was revised down in its latest S-1 amendment, for instance, and Haymaker has already gone from "upcoming" to "trading" as of today. Check the latest filing before making any decision — last week's numbers aren't guaranteed to hold by pricing day.
Full Company Profiles: History, Background, and Official
Websites
A closer look at each of these seven names: where they came from, who runs them, and where to find their official investor and company pages.
Orion180 Insurance Group Inc. (OIG)
Website: orion180.com
Orion180 was founded in 2016 (some company materials cite 2017) by CEO Ken Gregg and is headquartered in Melbourne, Florida. It started life as a Managing General Underwriter writing homeowners insurance for independent agents across the Southeast, built around a proprietary quoting and binding platform called MY180 that lets agents quote and bind policies within minutes. Things changed in February 2023, when the company launched Orion180 Insurance Co. and moved from MGU to a standalone insurance carrier, picking up more control over pricing and the customer experience along the way. These days it writes homeowners, flood, and landlord/dwelling policies across 14 states — Texas, California, and Florida among them — and reported roughly $601 million in managed premiums for the 12 months ended June 30, 2026. Orion180 carries an A- A.M. Best rating and has landed on the Inc. 5000 list of fastest-growing private companies four years running. RBC Capital Markets, UBS Investment Bank, and Raymond James are leading the IPO.
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Holtec Nuclear Corporation (HNUC)
Website: holtecinternational.com
Holtec Nuclear Corp is the newly formed public entity (incorporated December 2025) that will carry the operations of Holtec International, a company whose roots go back to the 1980s as a small, niche nuclear supplier. Still controlled by founder Dr. Krishna P. Singh, Holtec has since become the dominant player in spent nuclear fuel storage — holding over 90% U.S. market share in wet fuel storage and roughly 75% in dry fuel storage as of early 2026. Its legacy storage and decommissioning business generated close to $990 million in revenue in the year ended March 2026. But the more ambitious bets are elsewhere: restarting the Palisades Nuclear Generating Station in Michigan, which would be the first time a decommissioned U.S. nuclear plant has come back online, and commercializing its SMR-300 small modular reactor at the Krishna P. Singh Technology Campus in Camden, New Jersey. Palisades hit a major milestone in August 2026 when fuel assemblies started loading into the reactor core, and Holtec has also picked up government backing abroad, including a £30 million UK grant to build out its SMR presence there.
Electra Therapeutics, Inc. (ETRA)
Website: electratx.com
Electra Therapeutics was founded in 2018 by Adam Rosenthal, Ph.D. and Vijay Lathi, and is based in South San Francisco. It's a late clinical-stage biopharmaceutical developer working on a new class of precision medicines built around signal regulatory proteins (SIRP), a family of receptors expressed on specific immune cells. The lead candidate, ipsoprubart, is currently in a global Phase 2/3 registrational trial for secondary hemophagocytic lymphohistiocytosis, a rare and severe immune condition, and has already picked up Breakthrough Therapy designation from the FDA. Electra has raised around $300 million in venture funding, from investors including EQT Life Sciences, Sanofi Ventures, Mubadala Capital, and HBM Healthcare Investments — the most recent Series C closed at about $183 million in October 2025. It's a lean operation, with roughly 46 employees and about $97.7 million in cash as of mid-2026. Jefferies, TD Cowen, Evercore ISI, and Cantor Fitzgerald are leading the IPO.
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Bamboo Insurance Services, Inc. (BMB)
Website: bambooinsurance.com
Bamboo was founded in 2018 by CEO John Chu, a longtime insurance executive, largely in response to major insurers pulling back from California's wildfire-exposed homeowners market. Based in Midvale, Utah, it built a tech-enabled, data-driven MGU model designed specifically to price and manage risk in complex, high-hazard regions traditional carriers were avoiding. Ownership has changed hands a couple of times as the company scaled: White Mountains Insurance Group took a roughly 70% controlling stake in 2023–2024 for about $285 million, and CVC Capital Partners then bought a majority stake in 2025 at a valuation of $1.75 billion. Managed premiums grew from about $66.6 million in 2022 to $696.1 million in 2025, and 2025 also marked Bamboo's first expansion outside California, into Texas. J.P. Morgan, Morgan Stanley, Deutsche Bank Securities, Evercore ISI, and Wells Fargo Securities are leading the NYSE listing.
Amaero Inc. (AMRO)
Website: amaero.com
Amaero's history runs longer than most on this list. It was originally incorporated in Australia in 2019 as Amaero International Limited (later Amaero Ltd), and completed an IPO on the Australian Securities Exchange under the ticker 3DA that same December. The company makes high-purity refractory alloy and titanium powders used in 3D printing for defense, aerospace, space, and medical applications, with its main U.S. facility in McDonald, Tennessee. Looking to get closer to U.S. capital markets — and to better position itself with defense and aerospace customers who want domestically sourced materials — Amaero formed a Delaware corporation, Amaero Inc., in February 2026 and completed a redomiciliation from Australia to the U.S. that June, with the original ASX-listed entity becoming a subsidiary of the new holding company. It's applied to list on the Nasdaq Global Select Market under AMRO, with Stifel, Baird, and Lake Street running the offering.
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Siyata PTT (PTT)
Website: siyata.net
This one has a slightly messier corporate history. The original company, Siyata Mobile Inc., was founded by CEO Marc Seelenfreund and built a business around rugged Push-to-Talk over Cellular handsets and in-vehicle communication systems for first responders, police, fire departments, utilities, and enterprise customers — it previously traded on Nasdaq as SYTA. In October 2025, Siyata Mobile merged with Core Gaming, and the combined company was renamed Core AI Holdings, Inc., repositioned as an AI holding company in the process. Siyata PTT Inc. is the spun-out continuation of the original push-to-talk hardware business, still run by the same management team and serving the same first-responder and enterprise customers, now heading toward its own separate Nasdaq listing under PTT.
Haymaker Acquisition Corp V (HYACU)
Website: haymakerinc.com
Haymaker Acquisition Corp V is the fifth blank-check company formed by brothers Steven and Andrew Heyer. Steven previously served as CEO of Starwood Hotels & Resorts Worldwide and COO of The Coca-Cola Company; Andrew founded and runs Mistral Equity Partners, a consumer-focused private equity firm dating back to 2007. Their SPAC track record includes the original Haymaker Acquisition Corp, which merged with OneSpaWorld Holdings (NASDAQ: OSW) in 2019; Haymaker II, which combined with GPM Investments and ARKO Corp (NASDAQ: ARKO) in 2020; Haymaker III, which merged with hormone optimization company biote (NASDAQ: BTMD) in 2022; and Haymaker 4, which completed a business combination with Suncrete earlier in 2026. A separate attempt, Haymaker Acquisition IV, was filed in 2022 but withdrawn before completing an IPO. Haymaker V priced its $250 million offering at $10.00 per unit on September 16, 2026, and started trading on the NYSE the following day, with an eye toward a future merger in the industrial or consumer products and services space. Cantor and William Blair are joint book-runners.
Why IPO Season Matters for Everyday Investors
You might be wondering why a regular retail investor should care about any of this — isn't IPO investing usually a game for hedge funds and institutional money?
Not so much anymore. Modern US brokers let everyday investors get access to newly listed shares within minutes, sometimes seconds, of a stock hitting NYSE or Nasdaq trading. That accessibility is exciting, but it also means retail investors are exposed to more volatility from brand-new, thinly-traded stocks than they would have been a decade or two ago.
And honestly, IPOs are just fun to follow. They offer a window into which industries are pulling in capital right now — insurance tech, nuclear energy, biotech, blank-check vehicles — and watching the calendar over time tells you a lot about where Wall Street's attention (and money) is actually flowing.
This Month's IPO Lineup at a Glance
A rundown of the deals currently on the calendar, based on Nasdaq's IPO overview listings.
Orion180 Insurance Group (OIG) is targeting the NASDAQ Global Select market, pricing between $15.00 and $17.00 on 20,000,000 shares, with an expected offer amount around $391 million and a listing date of September 18. As a property and casualty insurer, Orion180 is stepping into a sector that's had a rough few years with climate-related claims volatility, though insurers with disciplined underwriting have found real opportunity as pricing has hardened across the industry.
Holtec Nuclear Corp (HNUC) is the biggest deal on this list by far, aiming for $15.00 to $18.00 on 50,000,000 shares — an offer amount north of $1 billion — with a Nasdaq listing also set for September 18. Nuclear has become a genuinely hot theme again, largely on the back of massive electricity demand from AI data centers and a broader push toward reliable, carbon-free baseload power. A deal this size says something about how much institutional appetite exists for the nuclear supply chain right now.
Electra Therapeutics (ETRA) is pricing between $14.00 and $16.00 on 21,666,667 shares, targeting roughly $398.7 million, with a NASDAQ Global Select listing also expected around September 18. As a clinical-stage biotech, Electra sits in a category that comes with higher risk and higher potential reward — these stocks are notoriously binary, often living or dying on trial data years down the road.
Bamboo Insurance (BMB) is headed to the NYSE with a price range of $18.00 to $20.00 on 35,000,000 shares, targeting about $805 million, with a September 23 expected date. Like Orion180, it's entering the insurance space, but the NYSE listing and larger deal size suggest Bamboo is aiming for a higher institutional profile out of the gate.
Amaero (AMRO) is listing on the Nasdaq Global Select market at $7.06 per share across 7,456,500 shares — around $60.5 million total — expected September 23. That's a notably smaller deal than the others here, which usually means more volatility once trading starts.
Haymaker Acquisition Corp V (HYACU) is the NYSE-listed SPAC in the group, pricing at the standard $10.00 per unit across 25,000,000 shares for a $250 million offer amount, and it already began trading on September 17. SPACs work differently than a traditional IPO: you're essentially investing in a shell company that plans to merge with a private business later, so the real story here depends entirely on what target Haymaker eventually lands on.
Siyata PTT (PTT) rounds things out with a NASDAQ Capital Market listing of 6,112,327 shares, expected September 30. Being on the Capital Market tier rather than Global Select usually means lower liquidity and sharper price swings than the larger listings above.
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Insurance IPOs: Why Two Deals Are Hitting at Once
It's worth pausing on the fact that Orion180 and Bamboo, both insurance-focused, are going public within days of each other. That's not really a coincidence — it reflects a broader trend of insurers going public after years of hardening premium pricing across property and casualty markets.
When insurers can charge more for coverage, often after a stretch of costly claims from severe weather, profitability tends to improve, and that makes it an attractive window for private insurers to go public and capitalize on stronger investor sentiment toward the sector. If you're digging into either of these names, pay close attention to loss ratios, reinsurance arrangements, and geographic concentration. Insurance is a business where the details in the numbers matter far more than the pitch deck.
Why Nuclear Energy IPOs Are Having a Moment
Holtec is the standout deal size-wise here, which isn't surprising given how much attention nuclear power has gotten lately. Data centers running AI workloads use enormous amounts of electricity, and tech companies have increasingly turned to nuclear power, including small modular reactors, as a reliable, always-on energy source that doesn't depend on the weather the way solar and wind do.
For long-term investors, nuclear-adjacent stocks are more of a multi-year infrastructure theme than a quick trade. Regulatory timelines, construction costs, and government policy all factor into how quickly this sector actually delivers returns, so patience matters here more than almost anywhere else on this list.
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Biotech IPOs: High Risk, High Reward
Electra falls into the classic clinical-stage biotech bucket, and if there's one category on this list that deserves extra caution, it's this one. Companies at this stage typically don't have approved, revenue-generating products yet — their value is tied almost entirely to what the market expects from future clinical trial results.
That means these stocks can swing dramatically on a single piece of trial data, in either direction. If you want biotech exposure, many experienced investors prefer spreading the risk across several names, or a biotech-focused ETF, rather than betting heavily on one clinical-stage company's pipeline.
What About SPACs Like Haymaker Acquisition Corp V?
SPACs had a wild run a few years back, then fell out of favor as a lot of blank-check mergers underperformed. Haymaker V is this structure making its way back onto the IPO calendar, and unlike everything else on this list, it's no longer "upcoming" — it priced its 25,000,000-unit offering at $10.00 per unit on September 16 and started trading on the NYSE the next day.
Here's roughly how it works: you're buying into a shell company holding cash in trust, with management promising to find and merge with a private business within a set timeframe. Until that target is announced, you're really just investing in management's track record and the $10 trust value, not an operating business. If you're considering a SPAC at all, look closely at the sponsor team's history with prior deals — that's usually the best signal for how the next chapter plays out.
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Smaller-Cap IPOs: Amaero and Siyata PTT
Amaero and Siyata PTT are both considerably smaller deals than the rest of this list. Smaller offer sizes usually mean lower trading liquidity once shares list, which can translate into wider bid-ask spreads and sharper swings in both directions.
That doesn't automatically make them bad investments. It just means they call for a different risk mindset — these are names where doing your own research into the underlying business, rather than chasing IPO-day hype, actually pays off.
How to Actually Evaluate an IPO Before Investing
When a new IPO calendar comes out, I run through more or less the same checklist before deciding whether a name is worth real research time.
First, the offer size and pricing range relative to the sector. A deal north of $1 billion, like Holtec's, signals serious institutional demand, while something like Amaero's roughly $60 million raise points to a name likely to see more price volatility.
Second, which exchange tier it's listing on. NASDAQ Global Select generally has stricter listing standards than NASDAQ Capital Market, which can be a useful, if imperfect, signal of company size and stability.
Third, whether I can actually explain the business model in plain English. If I can't sum up what a company does and how it makes money in two sentences, that's usually a sign I need to sit with the prospectus a bit longer before considering an investment.
Fourth, lock-up periods. Most IPOs come with a 90- to 180-day window where insiders can't sell shares. Once that period ends, a wave of selling can sometimes put pressure on the stock, which is worth watching if you're already holding shares.
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Should Beginners Even Buy IPO Stocks?
For most beginner investors, I'd treat IPOs as a small, speculative slice of a portfolio rather than a core holding. New listings tend to be more volatile than established, cash-flow-positive companies with years of public trading history and analyst coverage behind them.
If you're just getting started in US stocks, building a foundation with broad index funds and well-established companies first, then adding a small allocation to interesting IPOs later, tends to work out better than jumping in headfirst on day-one listings.
Frequently Asked Questions
How can I invest in an upcoming IPO?
Most major US brokers let you place interest in upcoming IPOs, though share allocation for retail investors isn't guaranteed and often depends on your broker and account size. You can also just buy shares on the open market once trading begins on NYSE or Nasdaq.
Is it risky to buy a stock on its IPO day?
Usually, yes. There's not much price history to go on yet, and demand often outstrips the number of shares actually available, so prices can swing hard in either direction on day one. A lot of investors just wait a few weeks or months and let things settle before jumping in — not a bad instinct, honestly.
What's the difference between NASDAQ Global Select and NASDAQ Capital Market?
Global Select is the tier with the tougher financial and liquidity bar to clear, so it tends to draw bigger, more established names. Capital Market exists for smaller companies, and trading there is usually thinner as a result.
What is a SPAC and how is it different from a traditional IPO?
Think of a SPAC as a shell company — it goes public first, raises a pile of cash, and only later goes looking for a private business to merge with. That's basically a back-door way of taking a company public. A traditional IPO skips all that: an actual operating business sells shares straight to the public from day one.
Why do biotech IPOs seem so volatile?
Many biotech companies going public are pre-revenue, so their stock price is driven almost entirely by expectations around clinical trial outcomes and regulatory approvals rather than current earnings — which is exactly what creates those sharp swings around major news events.
Should I buy IPO stocks for long-term investing?
Some IPOs do turn into excellent long-term holds, but it usually takes time to prove out the business model, profitability, and competitive position after going public. Treating new IPOs as a small, higher-risk allocation rather than a core long-term holding tends to be the more balanced approach.
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Final Thoughts
This month's calendar is a good reminder of how varied the "IPO" label really is — insurance companies, a major nuclear energy player, a clinical-stage biotech, a SPAC, and a couple of smaller-cap listings, all hitting NYSE and Nasdaq within about two weeks of each other. Each one carries its own risk profile, and lumping them all together as "buy the IPO" was never really a strategy.
If any of these names catch your eye, read the prospectus before buying. IPO hype fades fast, but the fundamentals of the business are what actually determine whether a stock is still worth holding a year, five years, or ten years down the road.
Disclaimer:
This blog is for educational and informational purposes only. The views expressed here are general information and should not be considered financial or investment advice. Investing in the stock market involves risk, and you should consult a licensed financial advisor (SEC-registered where applicable) before making any investment decisions. The author and website are not responsible for any financial losses incurred.