Castelion Stock: A Payload of Potential
Explore opportunities to invest in Castelion stock before the IPO. Castelion raised a Series C in August 2026, valuing the startup at $13 billion.
Invest in upcoming IPOs at Tradestation — a top broker for retail IPO access. Start investing with just $500.
Table of Contents
Notable Castelion News
08/19/2026: Castelion Raises $1B Series C
07/06/2026: Castelion readies for U.S. Army, Navy demos
06/17/2026: Castelion Targets $12 Billion Valuation
Older News…
About Castelion
Castelion is a defense startup building low-cost, mass-producible hypersonic missiles for the U.S. military.
A hypersonic missile is a weapon capable of traveling at Mach 5 or faster while maneuvering through the atmosphere, making it harder to track and intercept than traditional ballistic missiles.
The company was founded by three SpaceX veterans, Bryon Hargis, Sean Pitt, and Andrew Kreitz, in late 2022 after recognizing the Pentagon needed more missiles.
Like the “new primes” Shield AI and Anduril, they realized the legacy contractors (Northrop Grumman, Lockheed Martin, Raytheon, etc.) weren’t innovating fast enough or reducing costs.
Castelion has chosen to build most of the missile in-house and advance the technology through frequent test flights (agile) instead of years of design (waterfall), akin to the SpaceX playbook.
Its flagship product is Blackbeard, a long-range hypersonic missile. It is also developing other strike and defensive systems as its funding, talent, and core competencies grow.
Castelion aims to maintain in-house control over its design, testing, and manufacturing rather than relying on a web of subcontractors and complicated supply chains.
The company is based in El Segundo, California, with additional sites in Texas.
It competes alongside the legacy contractors with a different plan, scaling faster, prioritizing automation, and using lower-cost materials.
With government contracts and substantial venture capital funding, it is well positioned to become a competitive business in the next generation of American missile defense.
Ownership
Castelion is a venture-backed startup owned by its founders, employees, and multiple venture capital firms.
Notable venture capital investors include Andreessen Horowitz, T. Rowe Price, The Carlyle Group, Altimeter Capital, Avenir Growth, General Catalyst, Space VC, Lightspeed, Interlagos Capital, Cantos Ventures, Lavrock Ventures, First In, BlueYard Capital, and Champion Hill Ventures.
Funding Rounds
| Round | Date | Est. Valuation | Raise Amount | Price |
|---|---|---|---|---|
| Series C | 08/18/26 | $13.0B | $1.0B | $524.18 |
| Series B | 12/04/25 | $2.8B | $350.0M | $123.26 |
| Debt | 01/28/25 | NA | $30.0M | NA |
| Series A | 01/28/25 | NA | $100.0M | $20.22 |
| Seed | 10/04/23 | NA | $14.2M | $1.33 |
| Source: Caplight |
Valuation
The latest confirmed Castelion valuation is $13 billion based on the August 2026 Series C funding round that raised $1 billion.
IPO Potential
Castelion is still a relatively young company (Seed round in 2023) that is likely at least a few years away from an IPO.
As a U.S. military contractor, its path to success relies on winning contracts and producing low-cost weapons. It is still in the early stages of selling to the government, but if it can demonstrate capabilities and keep costs down, it has a likely growth trajectory ahead.
Politics and the ruling party will play a role in its success, like all government contractors. But the defense budget is always large enough for many players to grab meaningful contracts.
If Castelion can demonstrate capabilities in both manufacturing and weapon effectiveness, venture investors anticipate that the startup will be competitive among larger players.
An S-1 filing is the most accurate sign that an IPO may be forthcoming.
The intent to move forward with an IPO is usually leaked to the press long before the S-1 filing becomes available to the public.
As of the Series C, leadership has not indicated its long-term public ambitions.
How to Invest in Castelion Stock
Castelion has raised capital at a large enough valuation that we expect to see new availability on secondary markets, and possibly a new funding round within the next 12 months.
U.S.-based accredited investors can typically find more opportunities than non-accredited investors, but monitor the pre-IPO venture funds for new investments.
Here are some potential options to own Castelion stock before, during, and after the IPO.
1. Invest Pre-IPO
Pre-IPO investment platforms may offer Castelion stock or equity through an investment vehicle (such as an SPV) for purchase as employees or early investors seek to sell some of their shares in lieu of waiting for an exit (IPO or acquisition).
Accredited investors may access these investments on secondary marketplaces or through syndication, provided they are registered on platforms or connected to a syndicate.
Monitor pre-IPO investing platforms such as Hiive, Augment, Forge Global, and EquityZen for share availability.
If shares become available, expect to pay at least a $10,000 investment minimum, often more.
Non-accredited investors can invest in pre-IPO companies via venture capital funds (both public and non-traded) targeted at retail investors.
2. Participate in the Castelion IPO through a broker
Retail investors can sometimes participate in IPOs to buy the stock at the IPO price.
Once reserved for Wall Street’s best (wealthiest) customers, retail investors are getting more opportunities to participate.
A handful of online brokers (like the ones listed below) allow investors to invest in IPOs with account balances as little as $1.
Here’s the complete list of the best brokers for IPO investing to learn more about IPO access for retail investors.
3. Buy Castelion stock after the IPO
Most investors will wait until after the IPO to invest. The Castelion IPO could be several years away or will never arrive.
Waiting for the IPO can be advantageous as more shares become liquid and established financials become more available.
High-demand companies can have exaggerated valuations when a stock opens for trading. In these cases, the advantage lies with the IPO investors who can sell on the euphoria.
But stock prices may fall after the first and second-quarter earnings reports expose the nuts and bolts of a company, and locked-up shares become liquid.
Stock price declines can be good entry points for recent IPO stock. Avoid buying overvalued shares immediately after the IPO due to lockup expirations and earnings disappointments.
However, the most disruptive companies outperform over the long term.
Conclusion
Castelion is in a compelling growth stage, backed by venture capital funding and pragmatic government interest.
But it still has a lot to prove, including whether it can actually deliver missiles at the scale and cost it promises.
However, the conviction is clear: build in-house, test constantly, iterate, and leapfrog the habits of the legacy primes.
Whether that translates into a durable business depends less on any single funding round, and more on contract wins and scaled manufacturing wins.
Investors should watch the headlines (and this web page) for reports on upcoming funding rounds and rising valuations. As its value grows, retail may start to see investment opportunities on the secondary exchanges.
We don’t expect an IPO in the next three years, and there’s no guarantee one will happen, as new fast-moving defense startups may consolidate to reduce costs.
So interested investors should assume pre-IPO access carries a long-term investment horizon. The company is worth watching precisely because it represents a genuine test of whether Silicon Valley’s build-fast approach can actually work in an industry built around decades-long procurement cycles.
Castelion News Archive
12/05/2025: Castelion Closes $350 Million Series B
01/29/2025: Castelion Announces Series A Funding
