Lightmatter is a private company and has not filed a registration statement for an IPO. The photonic-computing company closed a $400 million Series D on October 16, 2024, led by new investor T. Rowe Price with participation from GV and Fidelity Management and Research Co., at a $4.4 billion valuation, nearly quadrupling its prior $1.2 billion mark from roughly ten months earlier. Co-founder and CEO Nick Harris told Reuters at the time, 'This is probably our last private funding round,' an indirect signal about direction, not a stated date. As of the latest site review, no newer primary round has been publicly reported, and Lightmatter has not filed with the SEC. Separately, PitchBook's VC Exit Predictor, cited by Morningstar in July 2026, put Lightmatter's IPO probability at 94% alongside a broader wave of chip-startup listings that the same report said could face delays. Track SEC EDGAR and Lightmatter's own newsroom directly, not rumors or secondary-market chatter.
Segmara is an independent research site. Segmara does not sell, broker, or arrange share purchases. Nothing here is investment advice.
Key points
A CEO's own words point toward a listing
Lightmatter, a Boston-based photonic-computing company founded in 2017 by CEO Nick Harris and colleagues, closed a $400 million Series D on October 16, 2024, according to Crunchbase News. New investor T. Rowe Price led the round, with existing backers GV and Fidelity Management and Research Co. also participating, at a $4.4 billion valuation, nearly four times the $1.2 billion valuation the company held roughly ten months earlier after a $155 million round led by GV.
Harris told Reuters at the time, 'This is probably our last private funding round,' one of the more direct forward-looking statements from any founder tracked on this site. That is a stated expectation about direction, not a committed date, and Lightmatter has taken no further public step toward a listing since.
What an outside model says, and does not say
PitchBook's VC Exit Predictor, republished by Morningstar in July 2026 as part of a broader look at semiconductor-startup IPO plans, assigns Lightmatter a 94% IPO probability, based on the company's $820 million in disclosed capital raised and $4.5 billion last-known valuation, both figures broadly consistent with the October 2024 round.
That is a statistical estimate built from funding and market data, not a Lightmatter announcement. The same Morningstar report described a mid-2026 semiconductor-stock selloff, driven partly by a record-setting Shanghai IPO from Chinese chipmaker CXMT, as a headwind that could push chip-startup listings, including ones with high predicted probabilities, into late 2026 or 2027 rather than cancel them outright.
What would actually change the picture
Nothing here substitutes for a filing. A public S-1 on SEC EDGAR, or a specific date or underwriter announcement from Lightmatter leadership, would be the first verifiable signal that an actual IPO process has begun. Neither exists as of the latest site review.
Given Harris's own 2024 comment about the Series D likely being the company's last private round, and PitchBook's high probability score, Lightmatter looks directionally closer to a listing than many private companies. Directional confidence is still not a date, and any specific 'Lightmatter IPO date' circulating online remains speculation until the company or a filing says otherwise.
Private-share data lens
Public round-by-round marks are incomplete for this company. Segmara shows the listing mark and keeps the seed-to-IPO analysis focused on verifiable funding, tender, or secondary signals.
Segmara mark$89.19/unit · as of September 7, 2026
Indicative listing context
Stage
Date
Valuation / price signal
Why it matters
Seed / early
Private
Not reliably public
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Growth rounds
Private
Company and market sources vary
Use public sources and official company releases.
Segmara listing
Current
$89.19/unit · as of September 7, 2026
Indicative reference only, not a quote or an offer.
IPO status
Current
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Seed-to-IPO path
Illustrative completeness map. Longer bars mean stronger public data or more useful current pricing context, not lower risk.
Early data22%
Growth data46%
Segmara mark68%
IPO/public18%
AI-ready data summary
A structured extraction layer for this article: catalogue numbers, price context, chart values, and route-specific facts that search and AI systems can read directly from the page.
Metric
Value
Context
Canonical route
/blog/when-will-lightmatter-ipo
Stable URL path for AI and search extraction.
Article title
When Will Lightmatter IPO? Its CEO Called the Last Round 'Probably Our Last'
Main page topic.
Attached public sources
4
Number of citation links rendered at the bottom of the article.
Segmara listed companies
51
Live private-company listings in the public catalogue.
Priced listings
37
Catalogue listings with visible indicative or direct marks.
Listings without an indicative price
14
Catalogue listings where a public price is intentionally not invented.
Company
Lightmatter
Named company covered by this page.
Symbol label
LMTR
Segmara display symbol; not a public stock ticker unless separately stated.
Sector
Hardware
Catalogue sector used for comparison and internal linking.
Listing structure
Secondary
How the listing is categorized on Segmara.
Segmara mark
$89.19/unit · as of September 7, 2026
Visible listing mark, or no indicative price yet.
Sector peer count
2
Number of live Segmara listings in Hardware.
Structure peer count
26
Number of live Segmara listings categorized as Secondary.
Price rank
21 of 37
Ranked highest-to-lowest among Segmara listings with visible marks.
Price percentile
46th
Percentile among visible Segmara catalogue marks.
Catalogue median mark
$92.58
Median visible mark across priced Segmara listings.
Premium/discount to median
-4%
Difference between this listing mark and the catalogue median mark.
Data fingerprint chart
Listing price percentile46%
$89.19/unit · as of September 7, 2026 ranks 21 of 37 priced listings
Stage
Timing
Price / valuation signal
Interpretation
Formation
Private
Early ownership
The first value creation happens before ordinary public-market access.
Growth rounds
Private
Institutional repricing
Later rounds and tenders create the price history buyers study.
Segmara listing
Current
$89.19/unit · as of September 7, 2026
Indicative reference only, not a quote or an offer.
Exit path
Future
IPO, tender, acquisition, or continued private status
Liquidity timing remains company-specific.
Chart metric
Score
Interpretation
Listing price percentile
46 / 100
$89.19/unit · as of September 7, 2026 ranks 21 of 37 priced listings
Analytical lens
Search intent
Searches like 'When Will Lightmatter IPO? Its CEO Called the Last Round 'Probably Our Last'' are research questions: what a filing or a company statement confirms, what has only been reported, and what is still unknown.
What counts as a listing step
For an IPO, the primary record is a registration statement filed with the securities regulator of the listing market, such as an S-1 or F-1 on SEC EDGAR for a US listing. Funding rounds, valuations and secondary-market prices are context, not listing steps.
Segmara role
Segmara is an independent research site. It does not sell, broker, or arrange share purchases, and nothing on this page is investment advice.
How a company reaches a US listing
The SEC filing trail
DraftThe company can first submit a draft registration statement (DRS) for confidential SEC review.
S-1 or F-1The registration statement goes public on SEC EDGAR: Form S-1, or Form F-1 for many foreign companies. A company that used a draft must file publicly at least 15 days before its roadshow.
AmendmentsS-1/A or F-1/A amendments answer SEC comments, and one of them adds the expected price range.
PricingOnce the SEC declares the registration effective, the company sets the price with its underwriters and files the final prospectus, usually a 424B4.
First tradeThe shares start trading on the exchange named in the prospectus, such as Nasdaq or the NYSE.
Segmara Pro checks SEC EDGAR for Lightmatter filings every weekday and posts an alert in the members forum when one of these public filings appears. You can also check yourself with EDGAR full-text search.
No S-1 or F-1 exists for Lightmatter on SEC EDGAR as of the latest site review, even though CEO Nick Harris told Reuters in October 2024 that its Series D was 'probably our last private funding round.'
Lightmatter closed a $400 million Series D on October 16, 2024, led by new investor T. Rowe Price with GV and Fidelity Management and Research Co. participating, at a $4.4 billion valuation, up from a $1.2 billion valuation roughly ten months earlier; the company has raised $850 million in total, per its own statement to Crunchbase News.
PitchBook's VC Exit Predictor, cited by Morningstar in July 2026, assigns Lightmatter a 94% IPO probability, but the same report warned that a semiconductor-stock selloff could push chip-startup IPOs, including Lightmatter's, into late 2026 or beyond.
Risk notes
Rumor risk: unofficial dates, valuations, or funding details circulating on social media or forums are frequently wrong or outdated and should not be treated as confirmation of anything.
Illiquidity risk: any private-market interest, indicative marks, or pre-IPO share arrangements in a company that has not filed to go public can be difficult to exit and may not reflect a tradable price.
Timing risk: a company can pause, restart, or abandon IPO preparation at any stage, including after a confidential draft filing, so no step before an effective registration statement guarantees a listing will occur.
Segmara Pro: a weekly IPO brief plus SEC filing alerts for 60+ companies, including Lightmatter, from automated EDGAR checks every weekday, posted in the members forum; 7-day free trial, then $15 a month (plus any applicable tax). Research only, no share sales.
Can retail investors track private-company shares on Segmara?
Yes. The free Lightmatter tracker sends indicative marks by email, with no card and no documents. Segmara does not sell, broker, or arrange share purchases.
Why was this market historically hard for retail investors to reach?
Private-company share access has often moved through private equity firms, venture funds, insiders, institutions, and relationship-driven secondary networks. Segmara makes research simpler: anyone can follow named private companies for free, by email.
What is the easiest next step?
Open the free Lightmatter tracker first, email only. The IPO calendar is free, and Segmara Pro adds a weekly IPO brief.
Has Lightmatter confirmed an IPO date?
No. As of the latest site review, no S-1 or F-1 has been filed for Lightmatter. CEO Nick Harris told Reuters in October 2024 that the company's Series D was 'probably our last private funding round,' which points toward a future listing but sets no date.
What is Lightmatter worth?
The most recent verified figure is a $4.4 billion valuation, set by a $400 million Series D round that closed October 16, 2024. Total disclosed funding is $850 million, per the company's own statement. No newer primary round has been publicly reported as of the latest site review.
Is Lightmatter likely to IPO soon?
PitchBook's VC Exit Predictor, as cited by Morningstar in July 2026, rates Lightmatter's IPO probability at 94%, one of the highest scores among tracked chip startups. That is a third-party statistical model, not a company announcement, and the same report noted a 2026 semiconductor-stock selloff could delay the wider group of chip-startup IPOs it covers.
What does Lightmatter actually make?
Silicon-photonics hardware that uses light instead of electricity to move data between chips, aimed at reducing the energy consumption and improving the scalability of AI data centers. Founded in 2017 and based in Boston, the company was valued at $4.4 billion in its most recent disclosed round.
Next step
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Segmara is an independent research site. Segmara does not sell, broker, or arrange share purchases.