Similarweb officer plans $8.8M sale of 1M shares

Rhea-AI Filing Summary

SIMILARWEB LTD. (SMWB) received a notice that company officer Or Offer plans to sell ordinary shares under SEC Rule 144 through Oppenheimer & Co. Inc. The notice covers up to 1,000,000 ordinary shares, with a stated aggregate market value of $8,840,000, to be sold pursuant to a pre-arranged Rule 10b5-1 trading plan adopted on June 1, 2026.

The filing also reports recent Rule 144 sales of Similarweb ordinary shares over the prior three months, providing context on the scale and timing of Or Offer’s ongoing share-disposition program relative to the company’s total of 86,962,202 ordinary shares outstanding.

Key Figures

Shares proposed to be sold: 1,000,000 ordinary shares Aggregate market value of proposed sale: $8,840,000 Shares outstanding: 86,962,202 ordinary shares +5 more

8 metrics

Shares proposed to be sold 1,000,000 ordinary shares Maximum amount covered by the Form 144 notice

Aggregate market value of proposed sale $8,840,000 Value of the 1,000,000 shares referenced in the notice

Shares outstanding 86,962,202 ordinary shares Total ordinary shares of SIMILARWEB LTD. outstanding for this class

Shares sold August 13, 2026 574,605 shares Ordinary shares sold for $15,201,232.74 during the past three months

Proceeds August 13, 2026 $15,201,232.74 Aggregate sale price for 574,605 ordinary shares

Shares sold August 14, 2026 134,992 shares Ordinary shares sold for $1,197,865.01 during the past three months

Shares sold August 26, 2026 383,127 shares Ordinary shares sold for $3,449,637.20 during the past three months

Founder Shares acquired 3,026,291 shares Founder Shares of SIMILARWEB LTD. acquired on February 19, 2009 for cash

Key Terms

Rule 144, Rule 10b5-1 trading plan, Founder Shares, Authorized Signatory

4 terms

Rule 144 regulatory

"See the definition of "person" in 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.

Rule 10b5-1 trading plan regulatory

"The securities are being sold pursuant to a Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

Founder Shares financial

"Ordinary shares | 02/19/2009 | Founder Shares | SIMILARWEB LTD."

Founder shares are the ownership stakes given to the people who start a company, often with extra voting power or protections compared with ordinary shares. For investors, they matter because founders’ control and incentives influence decisions about strategy, hiring, and whether the company sells or stays independent — like a family that keeps majority voting rights in a household decision. High founder ownership can mean stable leadership but also a risk that outside shareholders have less influence.

Authorized Signatory regulatory

"Title: Authorized Signatory, Oppenheimer Israel (pursuant to delegation)"

FAQ

How many SIMILARWEB LTD. (SMWB) shares does Or Offer plan to sell under this Form 144?

The notice covers up to 1,000,000 ordinary shares of SIMILARWEB LTD., with a stated aggregate market value of $8,840,000. These proposed sales are to be executed through Oppenheimer & Co. Inc. under SEC Rule 144.

What portion of SIMILARWEB LTD. (SMWB) shares are outstanding compared with this planned Rule 144 sale?

SIMILARWEB LTD. reports 86,962,202 ordinary shares outstanding. The Form 144 notice covers up to 1,000,000 shares, providing investors with context on the potential size of Or Offer’s sales relative to the company’s total outstanding shares.

What prior SIMILARWEB LTD. (SMWB) share sales has Or Offer reported in the last three months?

The filing lists three prior sales of ordinary shares: 574,605 shares for $15,201,232.74 on August 13, 2026; 134,992 shares for $1,197,865.01 on August 14, 2026; and 383,127 shares for $3,449,637.20 on August 26, 2026.

Are the planned SIMILARWEB LTD. (SMWB) share sales by Or Offer under a Rule 10b5-1 trading plan?

Yes. The remarks state that the securities are being sold pursuant to a Rule 10b5-1 trading plan adopted on June 1, 2026, indicating a pre-arranged schedule for these Rule 144 sales.

What type of SIMILARWEB LTD. (SMWB) shares is Or Offer selling under this Form 144?

The notice covers ordinary shares of SIMILARWEB LTD. It also notes that the securities to be sold include Founder Shares acquired on February 19, 2009 for cash, tying the proposed sales to Or Offer’s long-standing holdings.

Who is the broker handling Or Offer’s planned SIMILARWEB LTD. (SMWB) Rule 144 sales?

The planned sales of SIMILARWEB LTD. ordinary shares are to be executed through Oppenheimer & Co. Inc., located at 85 Broad Street, New York, NY 10004, as listed in the securities information section.

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

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Available on EDGAR 09/08/2026 - 10:45 AM Accepted by SEC EDGAR 09/08/2026 - 10:44 AM Learn about SEC filing dates

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	0001910424
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	SIMILARWEB LTD.
SEC File Number	001-40394
Address of Issuer	33 Yitzhak Rabin Rd. Givatayim ISRAEL 5348303
Phone	972 (73) 320-4086
Name of Person for Whose Account the Securities are To Be Sold	Or Offer
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	Officer

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
Ordinary shares	Oppenheimer & Co. Inc. 85 Broad St. New York NY 10004	1000000	8840000.00	86962202	09/08/2026	NYSE

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 *
Ordinary shares	02/19/2009	Founder Shares	SIMILARWEB LTD.			3026291	02/19/2009	Cash

* 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
Or Offer 33 Yitzhak Rabin Rd. Givatayim L3 5348303	Ordinary shares	08/13/2026	574605	15201232.74
Or Offer 33 Yitzhak Rabin Rd. Givatayim L3 5348303	Ordinary shares	08/14/2026	134992	1197865.01
Or Offer 33 Yitzhak Rabin Rd. Givatayim L3 5348303	Ordinary shares	08/26/2026	383127	3449637.20

144: Remarks and Signature

Remarks	The securities are being sold pursuant to a Rule 10b5-1 trading plan adopted on 06/01/2026
Date of Notice	09/08/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	06/01/2026
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	Or Offer By: /s/ Yohanan Azriel Title: Authorized Signatory, Oppenheimer Israel (pursuant to delegation)
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)