Private company · employee equity guide

CCommonwealth Fusion Systems logo

What is Commonwealth Fusion Systems stock worth?

Commonwealth Fusion Systems (CFS) is on a mission to deliver clean fusion energy to the planet fast enough to matter for humanity’s biggest challenges.It’s urgent. The gap between the energy we need and the energy we have is widening every day. Fusion is a critical part of the energy transition away from fossil fuels, a new chapter for the world’s energy supply.We’re committing to delivering fusion power plants and a full-fledged fusion energy industry as we’ve delivered on other promises. Like the world’s strongest high-temperature superconducting magnet, the game-changing technology that’s m

Estimated share price

Members onlySee the real chart, freeNo card. Takes about a minute.

Commonwealth Fusion Systems has an observed estimated price: most recent data 2026-09-15, daily history back to 2023-12-13.

Estimated from live trades and accepted bids across employer liquidity programs, institutional trades, broker trades, and pre-IPO marketplaces. Private shares are illiquid and transfer-restricted; estimates are educational, not an offer or advice. The preview above is blurred and illustrative. How this is calculated

About Commonwealth Fusion Systems

Employees
1,099
Founded
2018
Industry
Energy Technology
Website
cfs.energy

Weighing a Commonwealth Fusion Systems offer?

Upload the offer letter to see what the equity is approximately worth at today's estimated price. No account needed.

X-ray an offer

Leaving Commonwealth Fusion Systems? Mind the window.

If you hold options, leaving usually starts a post-termination exercise clock, often 90 days. Miss it and vested options can expire worthless; exercise blindly and you may owe real money (including possible AMT) on shares you can't yet sell. Neither panic nor autopilot is a plan. Knowing your window, your exercise cost, and the current estimated price is.

Track my window freeUpload your grant doc. We extract the window and set the reminders.

Commonwealth Fusion Systems in the last 12 months

  • 1 funding round

Covered by 21 distinct publications since 2025-08-28.

Commonwealth Fusion Systems news timeline

Commonwealth Fusion Systems equity, answered plainly

Is Commonwealth Fusion Systems a public company?

No. Commonwealth Fusion Systems is privately held, which is exactly why its share price doesn't show up in your brokerage app. The company (founded in 2018, operating in energy technology, with roughly 1,099 employees) remains private even at that scale. Its shares still change hands between eligible buyers and sellers on the secondary market, producing an observable estimated price.

What is Commonwealth Fusion Systems' stock price?

Commonwealth Fusion Systems has an observed estimated share price from secondary-market activity, updated as new data is observed. Its observed price history runs back to 2023-12-13. ExitCue members see the current estimate and its full history free, along with what their own grants are approximately worth at that price.

Can you sell Commonwealth Fusion Systems stock before an IPO?

Sometimes. Private-share sales depend on Commonwealth Fusion Systems' transfer restrictions, rights of first refusal, and whether the company runs tender offers or permits secondary sales. Your grant documents and the company's policies govern, but "hard to sell today" is not the same as "worth zero."

What happens to my Commonwealth Fusion Systems options if I leave?

Most option grants have a post-termination exercise window, commonly 90 days, sometimes longer, after which unexercised options expire worthless. The exact terms are in your grant documents. ExitCue reads those documents, tracks the deadline, and reminds you before the window closes.

How much is my Commonwealth Fusion Systems equity worth?

Multiply what you hold by the estimated share price, separating vested from unvested, and netting out strike prices for options. That's precisely the arithmetic ExitCue does for you, continuously, at the current observed estimate. It's an educational estimate, not a guarantee, and a far better anchor than the $0 the internet suggests.

What's the difference between Commonwealth Fusion Systems' 409A valuation and what its shares trade at?

The 409A is a tax-compliance appraisal, usually conservative, used to set option strike prices. Secondary-market pricing reflects what buyers and sellers actually agree to. The two frequently differ, which is why evaluating an offer on the 409A alone undersells (or oversells) it.

When will Commonwealth Fusion Systems IPO?

Unless Commonwealth Fusion Systems has publicly announced a listing, nobody knows, including the people who sound confident on forums. The practical upside of secondary markets is that you don't have to wait for an IPO to know approximately what the shares trade at.

Do my unvested Commonwealth Fusion Systems RSUs count for anything?

Unvested equity isn't yours yet, but it has an estimable value and a schedule. Seeing vested and unvested value separately, in dollars at the current estimated price, turns "some RSUs" into a number you can plan around.

General educational information, not advice about your specific situation. Grant terms vary; your documents govern.

Work out what your Commonwealth Fusion Systems equity is worth

These calculators take your own numbers and need no account.

New to this? Learn explains grant types, vesting and cliffs, and where an estimated share price comes from — in plain language.

Other private companies with observed prices

Company logos provided by Brandfetch.