SenesTech: Glenbrook reports 38.04% ownership stake

Glenbrook says future board proposals or director nominations remain possible, but it has made no specific decision.

Rhea-AI Filing Summary

SenesTech, Inc. (SNES) is the issuer in an amended ownership disclosure reporting Glenbrook Capital Management’s beneficial ownership of 2,063,098 common shares, or 38.04% of the class, with shared voting and dispositive power. The percentage is based on 5,423,542 shares outstanding as of August 4, 2026.

Glenbrook says approximately $4.33 million, excluding brokerage commissions, was paid to acquire the securities using general working capital of the Glenbrook Funds and Accounts; its transactions during the prior 60 days were all in the open market. It may discuss board composition and governance with directors, management and others, and may recommend changes, seek to fill vacancies, or propose or nominate director candidates, depending on discussions and other factors. Glenbrook says it has made no specific decision and gives no assurance it will take such action.

Key Figures

Beneficial ownership: 2,063,098 shares Percentage of class: 38.04% Shares outstanding: 5,423,542 shares +1 more

4 metrics

Beneficial ownership 2,063,098 shares SenesTech common stock

Percentage of class 38.04% Reported beneficial ownership

Shares outstanding 5,423,542 shares As of August 4, 2026; basis for reported ownership percentage

Purchase amount Approximately $4.33 million Paid to acquire the securities, excluding brokerage commissions

Key Terms

beneficially owned, Shared Voting Power, Shared Dispositive Power, margin accounts

4 terms

beneficially owned regulatory

"2,063,098 shares beneficially owned"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

Shared Voting Power regulatory

"Shared Voting Power 2,063,098.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

Shared Dispositive Power regulatory

"Shared Dispositive Power 2,063,098.00"

margin accounts financial

"Positions in the shares of Common Stock may be held in margin accounts"

A margin account is a brokerage account that lets an investor borrow money from the broker to buy more securities than they could with cash alone, using the securities in the account as security for the loan. Think of it like a mortgage for stock purchases: borrowing increases potential gains but also magnifies losses, can trigger a forced sale if the account falls below required limits, and carries interest costs—factors investors must manage carefully.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many SNES shares does Glenbrook Capital Management report owning?

Glenbrook Capital Management reports beneficial ownership of 2,063,098 SenesTech common shares, representing 38.04% of the class, with shared voting and dispositive power.

What could Glenbrook do about SenesTech’s board?

Glenbrook may recommend changes to the Board, seek to fill a vacancy, or propose or nominate director candidates for election at a stockholder meeting. It says any action would depend on discussions and other factors, and it has made no determination about a specific course of action.

How were Glenbrook’s SNES share purchases funded?

Glenbrook says purchases were funded from the general working capital of the Glenbrook Funds and Accounts. Common shares may be held in margin accounts; because those accounts may also hold other securities, the amount of margin used, if any, may not be determinable.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 10/19/2026 - 05:37 PM EDT Accepted by SEC EDGAR 10/19/2026 - 05:36 PM EDT Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 1)

SenesTech, Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

81720R604

(CUSIP Number)

Glenbrook Capital Management
2207, Suite B, Bellanca St.,
Minden, NV, 89423
650-441-9525

Ele Klein & Danny Goldstein
McDermott Will & Schulte LLP, 919 Third Avenue
New York, NY, 10022
212-756-2446

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

10/15/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

schemaVersion:

SCHEDULE 13D

CUSIP Number(s): 81720R604

1

Name of reporting person

GLENBROOK CAPITAL MANAGEMENT

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

NEVADA

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 2,063,098.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 2,063,098.00

11

Aggregate amount beneficially owned by each reporting person

2,063,098.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

38.04 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.0001 per share
(b)	Name of Issuer: SenesTech, Inc.
(c)	Address of Issuer's Principal Executive Offices: 13430 NORTH DYSART ROAD, SUITE 105, SURPRISE, ARIZONA , 85379.
Item 1 Comment: This Amendment No.1 ("Amendment No.1") amends the statement on Schedule 13D field with the SEC on July 23, 2026 (as amended from time to time, the "Schedule 13D") with respect to the Common Stock of the Issuer. This Amendment No. 1 amends Item 2(b), 3, 4, 5(a)-(c), and 7 as set forth below. Capitalized terms used herein and not otherwise defined in this Amendment No. 1 have the meanings set forth in the Schedule 13D.
Item 2.	Identity and Background
(b)	Item 2(b) is hereby amended and restated in its entirety as follows: The principal business address of each of the Covered Persons is 2207, Suite B, Bellanca St. Minden, NV 89423.
Item 3.	Source and Amount of Funds or Other Consideration
	Item 3 is hereby amended and restated as follows: Funds for the purchase of the securities reported herein were derived from the general working capital of the Glenbrook Funds and Accounts. A total of approximately $4.33 million (excluding brokerage commissions) was paid to acquire such securities. Positions in the shares of Common Stock may be held in margin accounts. Because other securities may be held in such margin accounts, it may not be possible to determine the amounts, if any, of margin used to purchase the shares of Common Stock.
Item 4.	Purpose of Transaction
	Item 4 is hereby amended and supplemented as follows: From time to time, the Reporting Person may engage with members of the board of directors of the Issuer (the "Board") and management, and may engage with other stockholders and other relevant parties, regarding, without limitation, its concerns regarding the composition of the Board, including whether the Board, as currently constituted, has the appropriate mix of skills, experience and perspectives to oversee the Issuer's strategy and execution, and issues regarding the size, composition and refreshment of the Board, the identification of potential director candidates, Board leadership and committee composition, and the Issuer's corporate governance practices. Depending on the outcome of such discussions and other factors the Reporting Person deems relevant, the Reporting Person may take such actions with respect to the composition of the Board as it deems appropriate, which may include recommending changes to the Board, seeking to fill any vacancy on the Board, or proposing or nominating one or more director candidates for election at a meeting of the Issuer's stockholders. The Reporting Person has not made any determination as to any specific course of action, and there can be no assurance that the Reporting Person will take any such action. On October 19, 2026, GCM issued a press release and public letter regarding the Issuer, which is attached as Exhibit 99.1 hereto and incorporated by reference herein.
Item 5.	Interest in Securities of the Issuer
(a)	Item 5(a) is hereby amended and restated as follows: See rows (11) and (13) of the cover page to this Schedule 13D for the aggregate number of shares of Common Stock and percentages of shares of Common Stock beneficially owned by the Reporting Person. The aggregate percentage of shares of Common Stock reported to be beneficially owned by the Reporting Person is based upon 5,423,542 shares of Common Stock outstanding as of August 4, 2026, as reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2026, filed with the SEC on August 6, 2026.
(b)	Item 5(b) is hereby amended and restated as follows: See rows (7) through (10) of the cover page to this Schedule 13D for the number of shares of Common Stock as to which the Reporting Person has the sole or shared power to vote or direct the vote and sole or shared power to dispose or to direct the disposition.
(c)	Item 5(c) is hereby amended and restated as follows: All transactions in the shares of Common Stock effected by the Reporting Person during the past sixty (60) days, which were all in the open market, are set forth in Schedule A hereto, and are incorporated herein by reference.
Item 7.	Material to be Filed as Exhibits.
	Item 7 is hereby amended and supplemented by adding the following: Exhibit 99.1 Press Release and Public Letter, dated October 19, 2026.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

GLENBROOK CAPITAL MANAGEMENT

Signature:	/s/ Robert W. Lishman
Name/Title:	Robert W. Lishman, Director
Date:	10/19/2026