Bryan Lee plans $43K Five9 stock sale under Rule 144

Bryan Lee filed a Rule 144 notice to sell 1,310 Five9 common shares and disclosed 14,313 shares sold in the prior three months under a 10b5-1 plan.

Rhea-AI Filing Summary

Five9, Inc. (FIVN) received a Rule 144 notice from Bryan Lee covering a planned sale of common stock. The notice lists 1,310 shares of common stock to be sold through Morgan Stanley Smith Barney LLC, with an aggregate market value of $43,583.70 and an anticipated sale date of September 8, 2026 on NASDAQ. The form also reports that Five9 had 74,723,531 shares of common stock outstanding at the time of the notice and that during the prior three months, Rule 10b5-1 sales for Bryan Lee totaled 14,313 shares of common stock for an aggregate sale price of $476,717.37.

Key Figures

Shares to be sold: 1,310 shares Aggregate market value of planned sale: $43,583.70 Shares outstanding: 74,723,531 shares +3 more

6 metrics

Shares to be sold 1,310 shares Planned Rule 144 sale of Five9 common stock

Aggregate market value of planned sale $43,583.70 Estimated value of 1,310 Five9 shares to be sold

Shares outstanding 74,723,531 shares Five9 common stock outstanding when the notice was prepared

Prior three-month sales 14,313 shares Rule 10b5-1 sales for Bryan Lee in the last three months

Aggregate value of prior three-month sales $476,717.37 Total proceeds from 14,313 Five9 shares sold on September 4, 2026

Approximate date of planned sale September 8, 2026 Anticipated date for sale of 1,310 shares on NASDAQ

Key Terms

Rule 144, Restricted Stock Units, 10b5-1, Aggregate market value

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.

Restricted Stock Units financial

"Common | 09/03/2026 | Restricted Stock Units | Issuer"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

10b5-1 regulatory

"10b5-1 Sales for BRYAN LEE 3001 Bishop Drive"

A 10b5-1 plan is a pre-set schedule that lets company insiders buy or sell shares according to written instructions made when they do not possess material, nonpublic information. Think of it as a timed automatic payment for stock trades: it helps insiders avoid accusations of trading on secret information and gives outside investors a clearer signal about whether sales are routine or potentially informative about the company’s prospects.

Aggregate market value financial

"Common | Morgan Stanley Smith Barney LLC ... | 1310 | 43583.70"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

FAQ

What does the Form 144 filing mean for Five9, Inc. (FIVN)?

The filing reports that Bryan Lee plans to sell 1,310 shares of Five9 common stock under Rule 144, with an expected aggregate market value of $43,583.70, and also discloses recent 10b5-1 plan sales. It is a notice of potential resale, not an offering by Five9.

How many FIVN shares is Bryan Lee planning to sell under this Form 144?

Bryan Lee plans to sell 1,310 shares of Five9 common stock. The notice shows an aggregate market value of $43,583.70 for these shares, with sales expected to occur on or about September 8, 2026 on NASDAQ through Morgan Stanley Smith Barney LLC.

What prior sales of FIVN stock did Bryan Lee report in the last three months?

The notice reports that in the past three months, Rule 10b5-1 sales for Bryan Lee totaled 14,313 shares of Five9 common stock, with an aggregate sale price of $476,717.37, on a transaction dated September 4, 2026.

How many Five9 (FIVN) shares were outstanding according to this filing?

The notice states that Five9 had 74,723,531 shares of common stock outstanding. This figure is provided as context for the Rule 144 sale and is separate from the 1,310 shares Bryan Lee plans to sell.

What type of security is Bryan Lee selling in this Form 144 for FIVN?

The notice covers common stock of Five9, Inc. It indicates that the securities to be sold relate to Restricted Stock Units acquired from the issuer, and that the planned sales will occur on NASDAQ through a brokerage firm.

Is the planned FIVN sale associated with a Rule 10b5-1 trading plan?

The filing labels prior three-month activity as “10b5-1 Sales for BRYAN LEE”, indicating those sales were under a Rule 10b5-1 plan. The current 1,310-share planned sale is reported on Form 144; the document links 10b5-1 specifically to the past 14,313-share sales.

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

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Available on EDGAR 09/08/2026 - 04:23 PM Accepted by SEC EDGAR 09/08/2026 - 04:22 PM 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	0002063775
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	FIVE9, INC.
SEC File Number	001-36383
Address of Issuer	3001 Bishop Drive, Suite 350 San Ramon CALIFORNIA 94583
Phone	9252012000
Name of Person for Whose Account the Securities are To Be Sold	BRYAN LEE
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
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	1310	43583.70	74723531	09/08/2026	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	09/03/2026	Restricted Stock Units	Issuer			1310	09/03/2026	N/A

* 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
10b5-1 Sales for BRYAN LEE 3001 Bishop Drive, Suite 350 San Ramon CA 94583	Common	09/04/2026	14313	476717.37

144: Remarks and Signature

Remarks
Date of Notice	09/08/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	09/03/2025
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/ Bryan Lee
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)