Magnite (MGNI) director Spillane sells 10,000 shares in open-market trade

Rhea-AI Filing Summary

MAGNITE, INC. director Robert F. Spillane reported an open-market sale of 10,000 shares of common stock on May 19, 2026 at a weighted average price of $13.33 per share. After this transaction, he directly owns 43,917 common shares.

The filing notes that the shares were sold in multiple trades at prices ranging from $13.32 to $13.355 per share, with full trade-by-trade details available upon request to the company, its security holders, or the SEC staff.

Insider Trade Summary

Net Seller: 10,000 shares ($133,300)

Net Sell 1 txn

Insider Spillane Robert F

Role null

Sold 10,000 shs ($133K)

Type	Security	Shares	Price	Value
Sale	Common Stock	10,000	$13.33	$133K

Holdings After Transaction: Common Stock — 43,917 shares (Direct, null)

Footnotes (1)

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Key Figures

Shares sold: 10,000 shares Weighted average sale price: $13.33 per share Post-transaction holdings: 43,917 shares +2 more

5 metrics

Shares sold 10,000 shares Open-market sale on May 19, 2026

Weighted average sale price $13.33 per share Common stock sale

Post-transaction holdings 43,917 shares Direct ownership after sale

Sale price range low $13.32 per share Lowest price within sale range

Sale price range high $13.355 per share Highest price within sale range

Key Terms

open-market sale, weighted average price, Form 4, Common Stock

4 terms

open-market sale financial

"The transaction was an open-market sale of MAGNITE common stock"

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.

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.

Form 4 regulatory

"was reported on a Form 4 insider filing with the Securities"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

Common Stock financial

"shares of MAGNITE common stock in an open-market transaction"

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.

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).

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^*

Spillane Robert F

(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)
05/19/2026

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	05/19/2026		S		10,000	D	$13.33(1)	43,917	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 price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.32 to $13.355, 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.

	/s/ Aaron Saltz, attorney-in-fact	05/21/2026
	** 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) disclose for Robert F. Spillane?

MAGNITE disclosed that director Robert F. Spillane sold 10,000 shares of common stock in an open-market transaction. The sale occurred on May 19, 2026, and was reported on a Form 4 insider filing with the Securities and Exchange Commission.

At what price did MAGNITE (MGNI) director Robert F. Spillane sell shares?

Robert F. Spillane sold his MAGNITE shares at a weighted average price of $13.33 per share. The filing states individual trades occurred between $13.32 and $13.355, with detailed breakdowns available upon request from the company or SEC staff.

How many MAGNITE (MGNI) shares does Robert F. Spillane hold after the reported sale?

Following the sale, Robert F. Spillane directly holds 43,917 shares of MAGNITE common stock. This post-transaction ownership figure is disclosed in the Form 4 and reflects his remaining direct equity position after the 10,000-share open-market sale.

What type of insider transaction was reported for MAGNITE (MGNI) on May 19, 2026?

The transaction was an open-market sale of MAGNITE common stock by director Robert F. Spillane. The Form 4 identifies the code “S,” meaning a sale in the open market or a private transaction, rather than an option exercise, gift, or tax withholding event.

Does the MAGNITE (MGNI) Form 4 mention multiple trade prices for the sale?

Yes. The Form 4 notes that the 10,000 shares were sold in multiple trades, with prices ranging from $13.32 to $13.355. It also states that detailed trade-by-trade price information will be provided upon request to the issuer, its security holders, or SEC staff.