MacroGenics ex-officer plans 15,811-share sale

A former officer of MacroGenics filed a Rule 144 notice to potentially sell 15,811 shares of MGNX common stock, following a prior 17,000-share sale in July 2026.

Available on EDGAR 09/21/2026 - 04:12 PM EDT Accepted by SEC EDGAR 09/21/2026 - 04:10 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

MACROGENICS INC (MGNX) has a former officer, Thomas Spitznagel, filing a notice of proposed sale of common stock under Rule 144. The notice covers the potential sale of 15,811 shares of common stock through Merrill Lynch, with an approximate sale date of September 21, 2026 on NASDAQ.

The filing also reports that during the prior three months, Spitznagel sold 17,000 shares of MacroGenics common stock on July 13, 2026.

Key Figures

Shares to be sold under Rule 144: 15,811 shares Aggregate market value of proposed sale: 65,530 Shares outstanding: 63,700,187 shares +3 more

6 metrics

Shares to be sold under Rule 144 15,811 shares Common stock of MacroGenics with approximate sale date September 21, 2026

Aggregate market value of proposed sale 65,530 Value associated with 15,811 shares of MacroGenics common stock in the notice

Shares outstanding 63,700,187 shares Shares of MacroGenics common stock outstanding referenced in the Form 144

Shares sold in past 3 months 17,000 shares Common stock of MacroGenics sold on July 13, 2026 by the same person

Aggregate market value of prior sale 75,529 Aggregate market value for 17,000 MacroGenics shares sold on July 13, 2026

Approximate date of proposed sale September 21, 2026 Date indicated for sale of 15,811 MacroGenics shares

Key Terms

Rule 144, aggregate market value, stock plan activity, securities to be sold

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.

aggregate market value financial

"Common ... 15811 | 65530 | 63700187 | 09/21/2026 | NASDAQ"

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.

stock plan activity financial

"Common | 09/21/2026 | Stock plan activity | Issuer"

securities to be sold financial

"144: Securities To Be Sold"

FAQ

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

What does the Form 144 filing for MGNX disclose?

It discloses that former officer Thomas Spitznagel filed a Rule 144 notice for the potential sale of 15,811 shares of MacroGenics common stock, with an approximate sale date of September 21, 2026 on NASDAQ.

How many MGNX shares may be sold under this Rule 144 notice?

The notice covers a potential sale of 15,811 shares of MacroGenics (MGNX) common stock. The approximate date of sale indicated in the filing is September 21, 2026.

Who is selling MacroGenics (MGNX) shares in this Form 144?

The potential sale is for the account of Thomas Spitznagel, identified as a former officer of MacroGenics Inc. The shares are to be sold through Merrill Lynch.

On what exchange are the MGNX shares in this Form 144 expected to trade?

The Form 144 indicates that the 15,811 shares of MacroGenics common stock covered by the notice are expected to be sold on NASDAQ.

What prior sales of MGNX stock by this person are reported?

The filing reports that 17,000 shares of MacroGenics common stock were sold for the account of Thomas Spitznagel on July 13, 2026 during the past three months.

What aggregate market value is associated with the MGNX shares in this Form 144?

The Form 144 lists an aggregate market value of 65,530 for the 15,811 shares of MacroGenics common stock proposed to be sold.

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	0001675464
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	MACROGENICS INC.
SEC File Number
Address of Issuer	9704 Medical Center Drive Rockville MARYLAND 20850
Phone	3012515172
Name of Person for Whose Account the Securities are To Be Sold	Thomas Spitznagel
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	Former 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	Merrill Lynch 1800 K St NW Suite 800 Washington DC 20006	15811	65530	63700187	09/21/2026	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	09/21/2026	Stock plan activity	Issuer			15811	09/21/2026	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
Thomas Spitznagel 9704 Medical Center Drive Rockville MD 20850	Common	07/13/2026	17000	75529

144: Remarks and Signature

Remarks
Date of Notice	09/21/2026
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	Thomas Spitznagel
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)