Tenable director proposes $731K sale of 15,000 shares

The reported prior-three-month sales include 15,000 common shares for $754,800.

Available on EDGAR 11/02/2026 - 02:51 PM EST Accepted by SEC EDGAR 11/02/2026 - 02:51 PM EST Learn about SEC filing dates

Rhea-AI Filing Summary

Tenable Holdings, Inc. (TENB) director Alexander Brooke Seawell gave notice of a proposed sale of 15,000 common shares, with an aggregate market value of $730,961.77. The approximate sale date is November 2, 2026. The shares are being sold from the Alexander Brooke Seawell Rev Trust and were acquired in Tenable's July 26, 2018 IPO.

Key Figures

Proposed shares: 15,000 common shares Aggregate market value: $730,961.77 Approximate sale date: November 2, 2026 +3 more

6 metrics

Proposed shares 15,000 common shares Proposed sale

Aggregate market value $730,961.77 Proposed sale

Approximate sale date November 2, 2026 Proposed sale

Shares outstanding 110,139,983 shares Count listed with the proposed sale

Prior three-month shares sold 15,000 common shares Sales reported during the prior three months

Prior three-month sale value $754,800 Sales reported during the prior three months

Key Terms

Rule 144, IPO, attorney-in-fact

3 terms

Rule 144 regulatory

"paragraph (a) of Rule 144"

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

IPO financial

"IPO"

An initial public offering (IPO) is the process by which a private company sells its shares to the public for the first time, making its ownership available on the stock market. This allows the company to raise money from a wide range of investors to fund growth or other goals. For investors, an IPO offers a chance to buy into a company early in its public journey, potentially benefiting if the company grows in value.

attorney-in-fact regulatory

"as attorney-in-fact for Alexander Brooke Seawell"

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

FAQ

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

How many TENB shares is Alexander Brooke Seawell proposing to sell?

He gave notice of a proposed sale of 15,000 common shares, with an aggregate market value of $730,961.77; the approximate sale date is November 2, 2026.

How many TENB shares did Alexander Brooke Seawell sell in the prior three months?

The reported prior-three-month sale was 15,000 common shares, with $754,800 in value.

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

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Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001197652
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Tenable Holdings, Inc.
SEC File Number	001-38600
Address of Issuer	6100 MERRIWEATHER DRIVE COLUMBIA MARYLAND 21044
Phone	410-872-0555
Name of Person for Whose Account the Securities are To Be Sold	SEAWELL A BROOKE
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Rockefeller Capital Management 2 embarcadero Center Suite 2320 San Francisco CA 94111	15000	730961.77	110139983	11/02/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common Stock	07/26/2018	IPO	TENB			15000	07/26/2018	Cash/Check

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Brooke Seawell c/o Tenable Holdings, Inc. 6100 MERRIWEATHER DRIVE Columbia MD 21044	Common Stock	11/02/2026	15000	754800.00

144: Remarks and Signature

Remarks	shares are being sold from THE ALEXANDER BROOKE SEAWELL REV TR, U/A 1/20/09
Date of Notice	11/02/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Audrey Skillern as a duly authorized representative of National Financial Services LLC, as attorney-in-fact for Alexander Brooke Seawell
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)