As of November 6, 2026, one holder's latest Schedule 13D or 13G filing report owning 5% or more of ESS Tech, Inc. The largest reported stake is Ayrton Capital LLC's, at 8.14%. 5 filings are on record since February 17, 2026 (Schedule 13G/A, August 13, 2026).
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Key facts
- · Reporting person: Alyeska Investment Group, L.P. · Sole voting: 0 · Shared voting: 1,400,000 · Sole dispositive: 0 · Shared dispositive: 1,400,000 · SCHEDULE 13G/A, 2026-08-14
- · Reporting person: Ayrton Capital LLC · Sole voting: 2,563,934 · Shared voting: 0 · Sole dispositive: 2,563,934 · Shared dispositive: 0 · SCHEDULE 13G/A, 2026-08-13
- · Holder: Alyeska Investment Group, L.P. · Percent: 5.15% · SCHEDULE 13G/A
- · Holder: Ayrton Capital LLC · Percent: 9.99% · SCHEDULE 13G
- · Holder: Alyeska Investment Group, L.P. · Percent: 7.14% · SCHEDULE 13G
ESS Tech, Inc. has 5 Schedule 13D or 13G filings on record since 2026-02-17. 1 holder's latest filing reports 5% or more of common stock, $0.0001 par value per share. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| Ayrton Capital LLC | 8.14% | 2,563,934 | SCHEDULE 13G/A, 2026-08-13 | 2026-06-30 |
| Alyeska Investment Group, L.P. | 4.76% | 1,400,000 | SCHEDULE 13G/A, 2026-08-14 | 2026-06-30 |
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More on ESS Tech, Inc. and the records around it.
ESS Tech, Inc. elsewhere on the record
- Leadership changes Sep 2026
- Form D filing Jul 2025
Companies that share a holder
- Ayrton Capital LLC also filed stake reports on 31 other companies: Bluejay Diagnostics, Inc. (Aug 2026), BTC Digital Ltd. (Aug 2026), DEFSEC Technologies Inc. (Aug 2026)
- Alyeska Investment Group, L.P. also filed stake reports on 81 other companies: ABUNDIA GLOBAL IMPACT GROUP, INC. (Aug 2026), Bakkt, Inc. (Aug 2026), BATTALION OIL CORP (Aug 2026)
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What the Full Report on ESS Tech, Inc. covers
The Short Answer
Which Company This Is
What They Do, And How The Money Works
Who Runs It, And How To Reach Them
The Money: Funding, Valuation, Runway
Who Pays Them, And Who They Are Up Against
Warning Bells
Sources
8 cited sources found
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Voting and dispositive power, as filed
| Reporting person | Sole voting | Shared voting | Sole dispositive | Shared dispositive | Filing |
|---|---|---|---|---|---|
| Ayrton Capital LLC | 2,563,934 | 0 | 2,563,934 | 0 | SCHEDULE 13G/A, 2026-08-13 |
| Alto Opportunity Master Fund, SPC - Segregated Master Portfolio B | 2,563,934 | 0 | 2,563,934 | 0 | SCHEDULE 13G/A, 2026-08-13 |
| Waqas Khatri | 2,563,934 | 0 | 2,563,934 | 0 | SCHEDULE 13G/A, 2026-08-13 |
| Alyeska Investment Group, L.P. | 0 | 1,400,000 | 0 | 1,400,000 | SCHEDULE 13G/A, 2026-08-14 |
| Alyeska Fund GP, LLC | 0 | 1,400,000 | 0 | 1,400,000 | SCHEDULE 13G/A, 2026-08-14 |
| Anand Parekh | 0 | 1,400,000 | 0 | 1,400,000 | SCHEDULE 13G/A, 2026-08-14 |
The latest filing identifies ESS Tech, Inc. by CUSIP 26916J205 and gives its principal executive office as 26440 SW Parkway Ave., Bldg. 83, Wilsonville, OR 97070 (SCHEDULE 13G/A, 2026-08-14).
What the percentages are based on
The percentages below are based on (i) 29,389,170 shares of Common Stock of the Issuer that were outstanding as of May 4, 2026; and (ii) 2,100,000 shares of Common Stock issuable on the exercise of the Warrants held by the Reporting Persons. The amount of shares outstanding was based upon a statement in the Issuer's 10-Q filed on May 7, 2026.Ayrton Capital LLC, SCHEDULE 13G/A, 2026-08-13
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2026-02-17 | Alyeska Investment Group, L.P. | 7.14% | SCHEDULE 13G |
| 2026-05-11 | Ayrton Capital LLC | 9.99% | SCHEDULE 13G |
| 2026-05-15 | Alyeska Investment Group, L.P. | 5.15% | SCHEDULE 13G/A |
| 2026-08-13 | Ayrton Capital LLC | 8.14% | SCHEDULE 13G/A |
| 2026-08-14 | Alyeska Investment Group, L.P. | 4.76% | SCHEDULE 13G/A |
Questions about who owns ESS Tech, Inc.
Who owns ESS Tech, Inc.?
On this page, one holder's latest ownership filing reports 5% or more of ESS Tech, Inc.: Ayrton Capital LLC (8.14%, Schedule 13G/A, filed 2026-08-13).
When did Ayrton Capital LLC buy into ESS Tech, Inc.?
The filings give report dates, not purchase dates. The earliest filing from Ayrton Capital LLC on this page is the Schedule 13G, filed 2026-05-11, reporting 9.99%; its latest, Schedule 13G/A filed 2026-08-13, reports 8.14%.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 5 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
Also on the record for ESS Tech, Inc.
| Date | Record | Figure | Our page | Source |
|---|---|---|---|---|
| June 18, 2026 | Leadership change: Rich Hossfeld departs, Director | — | Leadership changes | Source |
| April 15, 2026 | Leadership change: Michael Niggli departs | — | Leadership changes | Source |
| July 23, 2025 | Form D, private offering | $900K sold | Form D page | Source |
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Where this comes from
Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.
Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.