Cytek officer to sell 31,666 shares of stock

Cytek Biosciences, Inc. (CTKB) received a notice that officer Philippe Busque intends to sell 31,666 shares of common stock under Rule 144, with sales to be executed through Morgan Stanley Smith Barney LLC.

Rhea-AI Filing Summary

Cytek Biosciences, Inc. (CTKB) received a notice that officer Philippe Busque intends to sell 31,666 shares of common stock under Rule 144, with sales to be executed through Morgan Stanley Smith Barney LLC. The shares relate to a stock option exercise dated September 2, 2026. As context, common stock outstanding is listed as 129,983,253 shares as of September 2, 2026.

Key Figures

Shares to be sold: 31,666 shares Aggregate market value: $146,515.42 Shares outstanding: 129,983,253 shares +1 more

4 metrics

Shares to be sold 31,666 shares Common stock covered by the Rule 144 notice

Aggregate market value $146,515.42 Value of 31,666 CTKB shares subject to Rule 144

Shares outstanding 129,983,253 shares Cytek Biosciences common stock outstanding as of September 2, 2026

Filing date referenced September 2, 2026 Date tied to securities information and option exercise

Key Terms

Rule 144, stock option exercise, Securities To Be Sold, 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.

stock option exercise financial

"Common | 09/02/2026 | Stock Option Exercise | Issuer"

A stock option exercise is the act of using a previously granted right to buy shares of a company's stock at a specific, predetermined price by paying that price and receiving the shares. It matters to investors because exercising changes who owns the shares (which can dilute existing ownership), can trigger taxable events and shift potential gains or losses, and affects voting power and the company’s outstanding share count—like turning a voucher into an actual product that becomes part of circulating supply.

Securities To Be Sold financial

"144: Securities To Be Sold Common | 09/02/2026"

aggregate market value financial

"Common | Morgan Stanley Smith Barney LLC ... | 31666 | 146515.42"

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 insider sale has been signaled for CTKB in this Form 144?

Officer Philippe Busque has filed a Rule 144 notice indicating an intent to sell 31,666 shares of Cytek Biosciences common stock following a stock option exercise dated September 2, 2026.

How many Cytek Biosciences (CTKB) shares are covered by this Rule 144 filing?

The filing covers a proposed sale of 31,666 shares of Cytek Biosciences, Inc. common stock, to be sold through Morgan Stanley Smith Barney LLC.

What is the aggregate market value of the CTKB shares in this Form 144?

The 31,666 Cytek Biosciences common shares covered by the notice have an aggregate market value of $146,515.42, based on the figure stated in the filing for Rule 144 purposes.

How many Cytek Biosciences (CTKB) shares are outstanding as referenced in the filing?

The notice lists 129,983,253 shares of Cytek Biosciences common stock as outstanding as of September 2, 2026, providing context for the Rule 144 sale amount.

Through which broker will the CTKB Rule 144 shares be sold?

The filing states that the Cytek Biosciences common shares are to be sold through Morgan Stanley Smith Barney LLC Executive Financial Services, located at 1 New York Plaza, New York.

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

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Available on EDGAR 09/02/2026 - 04:13 PM Accepted by SEC EDGAR 09/02/2026 - 04:12 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	0001991396
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	CYTEK BIOSCIENCES, INC.
SEC File Number	001-40632
Address of Issuer	47215 Lakeview Blvd. Fremont CALIFORNIA 94538
Phone	(877) 922-9835
Name of Person for Whose Account the Securities are To Be Sold	PHILIPPE BUSQUE
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	31666	146515.42	129983253	09/02/2026	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	09/02/2026	Stock Option Exercise	Issuer			31666	09/02/2026	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

Nothing to Report

144: Remarks and Signature

Remarks
Date of Notice	09/02/2026
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/ Philippe Busque
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)