Magnite (NASDAQ: MGNI) director sells 37,337 shares in Rule 10b5-1 trade

Rhea-AI Filing Summary

MAGNITE, INC. director Douglas S. Knopper reported an open-market sale of 37,337 shares of common stock on June 16, 2026 at a weighted average price of $18.10 per share, with individual trade prices ranging from $18.00 to $18.25.

The transaction was executed under a pre-arranged Rule 10b5-1 trading plan adopted on December 12, 2025. Following this sale, Knopper directly holds 125,810 shares of Magnite common stock.

Insider Trade Summary 10b5-1

Net Seller: 37,337 shares ($675,800)

Net Sell 1 txn

Insider Knopper Douglas S

Role null

Sold 37,337 shs ($676K)

Type	Security	Shares	Price	Value
Sale	Common Stock	37,337	$18.10	$676K

Holdings After Transaction: Common Stock — 125,810 shares (Direct, null)

Footnotes (1)

1. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 12, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.00 to 18.25, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

Key Figures

Shares sold: 37,337 shares Weighted average sale price: $18.10 per share Sale price range: $18.00–$18.25 per share +2 more

5 metrics

Shares sold 37,337 shares Open-market sale of Magnite common stock on June 16, 2026

Weighted average sale price $18.10 per share Average price for the 37,337 shares sold

Sale price range $18.00–$18.25 per share Price range across multiple sale transactions

Shares owned after sale 125,810 shares Douglas S. Knopper’s direct Magnite holdings post-transaction

Trading plan adoption date December 12, 2025 Date Knopper adopted the Rule 10b5-1 trading plan

Key Terms

Rule 10b5-1 trading plan, weighted average price, open-market sale, Common Stock

4 terms

Rule 10b5-1 trading plan regulatory

"The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 12, 2025."

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.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

open-market sale financial

"transaction_action: "open-market sale""

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

Common Stock financial

"security_title: "Common Stock""

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

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Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Knopper Douglas S

(Last) (First) (Middle)

C/O MAGNITE, INC.

1250 BROADWAY, 9TH FLOOR

(Street)

NEW YORK NEW YORK 10001

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
MAGNITE, INC. [ MGNI ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/16/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	06/16/2026		S(1)		37,337	D	$18.1(2)	125,810	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 12, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.00 to 18.25, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

	/s/ Aaron Saltz, attorney-in-fact	06/17/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did Magnite (MGNI) director Douglas S. Knopper report?

Douglas S. Knopper reported selling 37,337 shares of Magnite common stock in an open-market transaction. The sale occurred on June 16, 2026, as part of a pre-arranged Rule 10b5-1 trading plan and was disclosed in a Form 4 filing.

At what price did Douglas S. Knopper sell Magnite (MGNI) shares?

The reported weighted average sale price was $18.10 per share. Individual trades were executed at prices ranging from $18.00 to $18.25, and the filing notes Knopper can provide detailed trade-by-trade pricing information upon request to interested parties.

How many Magnite (MGNI) shares does Douglas S. Knopper hold after this sale?

After the reported sale, Douglas S. Knopper directly holds 125,810 shares of Magnite common stock. This post-transaction balance is disclosed in the Form 4 and reflects his remaining direct ownership position following the 37,337-share open-market sale.

Was the Magnite (MGNI) insider sale made under a Rule 10b5-1 plan?

Yes. The filing states the sale was executed under a Rule 10b5-1 trading plan adopted by Douglas S. Knopper on December 12, 2025. Such plans pre-schedule trades, which can indicate routine portfolio management rather than discretionary timing.

What type of transaction is reported for Magnite (MGNI) in this Form 4?

The Form 4 reports an open-market sale of common stock, coded as “S” for sale. It involves 37,337 Magnite shares sold at a weighted average price of $18.10 per share, with prices spanning from $18.00 to $18.25 during the transaction.