MGNI
Magnite Inc
25.20$
-1.9%
vs. previous close
Closing price · As of: Sep 18, 2026
Ownership
Ownership Structure
Who owns Magnite Inc (MGNI)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 98.7% of the shares are freely tradable; institutional investors hold 94.2%.
Institutional ownership
?Share of the stock held by institutional investors (funds, banks, insurers) according to regulatory filings.
94.2%
Insiders
?Share of the stock held by the executives, founders and major shareholders of the company itself.
1.3%
Float
?Share of stock freely tradable on the market — not locked up in the hands of founders, insiders, or major shareholders.
98.7%
Short % of float
?Shares sold short as a percentage of the freely tradable float — high values signal many bets on falling prices.
8.7%
Shares Outstanding
?Total number of shares issued. Price times share count gives market cap.
143Mio.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| BlackRock Inc | 8.13 | 11,657,496 | +0.6 | 03/31/2026 |
| Vanguard Portfolio Management, LLC | 5.39 | 7,726,205 | +0.0 | 03/31/2026 |
| Vanguard Capital Management, LLC | 4.32 | 6,190,403 | +0.0 | 03/31/2026 |
| Wellington Management Company LLP | 4.21 | 6,044,492 | -34.2 | 06/30/2026 |
| Dimensional Fund Advisors, Inc. | 3.67 | 5,260,132 | +32.0 | 06/30/2026 |
| Boston Partners Global Investors, Inc | 3.50 | 5,013,835 | +6.2 | 06/30/2026 |
| American Century Companies Inc | 3.22 | 4,622,736 | -0.1 | 06/30/2026 |
| FMR Inc | 3.14 | 4,507,419 | -32.7 | 03/31/2026 |
| Capital Research Global Investors | 2.70 | 3,869,159 | -22.9 | 06/30/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Vanguard MStar Total Stk Mkt Idx Invest | 3.03 | 4,345,815 | +0.4 | 07/31/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Day David | CHIEF FINANCIAL OFFICER | 452,861 | 11,412,097 $ | Aug 15, 2026 | direct |
| Evans Katie Seitz | See Remarks | 441,800 | 11,133,360 $ | Sep 11, 2026 | direct |
| Barrett Michael G. | CEO | 392,670 | 9,895,284 $ | Aug 15, 2026 | direct |
| Buckley Sean Patrick | See Remarks | 293,060 | 7,385,112 $ | Aug 18, 2026 | direct |
| Buonasera David | CHIEF TECHNOLOGY OFFICER | 245,155 | 6,177,906 $ | Sep 14, 2026 | direct |
| Lam Rachel | Director | 230,620 | 5,811,624 $ | Aug 10, 2026 | direct |
| Saltz Aaron | CHIEF LEGAL OFFICER | 224,389 | 5,654,603 $ | Sep 10, 2026 | direct |
| Caine Paul | Director | 144,901 | 3,651,505 $ | Sep 10, 2026 | direct |
| Harden Sarah Patricia | Director | 114,751 | 2,891,725 $ | Aug 28, 2026 | direct |
| Gephart Brian | CHIEF ACCOUNTING OFFICER | 102,328 | 2,578,666 $ | Aug 15, 2026 | direct |
| Knopper Douglas S | Director | 88,473 | 2,229,520 $ | Aug 6, 2026 | direct |
| Spillane Robert F | Director | 57,715 | 1,454,418 $ | Sep 14, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Sep 14, 2026 | Buonasera David | CHIEF TECHNOLOGY OFFICER | Sell | 1,165 | 24.00 | 27,960 |
| Sep 14, 2026 | Spillane Robert F | Director | Sell | 10,363 | 23.76 | 246,225 |
| Sep 14, 2026 | Spillane Robert F | Director | Other | 10,363 | 5.17 | 53,577 |
| Sep 11, 2026 | Evans Katie Seitz | See Remarks | Sell | 13,997 | 24.00 | 335,928 |
| Sep 10, 2026 | Saltz Aaron | CHIEF LEGAL OFFICER | Sell | 40,000 | 23.41 | 936,400 |
| Sep 10, 2026 | Caine Paul | Director | Sell | 5,000 | 23.53 | 117,650 |
| Sep 9, 2026 | Evans Katie Seitz | See Remarks | Sell | 11,100 | 23.46 | 260,406 |
| Sep 8, 2026 | Evans Katie Seitz | See Remarks | Sell | 32,285 | 23.63 | 762,895 |
| Sep 8, 2026 | Evans Katie Seitz | See Remarks | Other | 13,546 | 5.16 | 69,897 |
| Sep 2, 2026 | Buonasera David | CHIEF TECHNOLOGY OFFICER | Sell | 1,043 | 25.00 | 26,075 |
| Sep 1, 2026 | Buonasera David | CHIEF TECHNOLOGY OFFICER | Sell | 5,371 | 23.42 | 125,789 |
| Aug 28, 2026 | Harden Sarah Patricia | Director | Sell | 18,436 | 24.00 | 442,464 |
| Aug 26, 2026 | Harden Sarah Patricia | Director | Sell | 30,550 | 23.31 | 712,121 |
| Aug 18, 2026 | Buckley Sean Patrick | See Remarks | Sell | 2,759 | 25.00 | 68,975 |
| Aug 17, 2026 | Buckley Sean Patrick | See Remarks | Sell | 8,271 | 24.31 | 201,068 |
| Aug 15, 2026 | Buonasera David | CHIEF TECHNOLOGY OFFICER | Other | 8,102 | 24.73 | 200,362 |
| Aug 15, 2026 | Buckley Sean Patrick | See Remarks | Other | 11,715 | 24.73 | 289,712 |
| Aug 15, 2026 | Saltz Aaron | CHIEF LEGAL OFFICER | Other | 5,627 | 24.73 | 139,156 |
| Aug 15, 2026 | Gephart Brian | CHIEF ACCOUNTING OFFICER | Other | 3,789 | 24.73 | 93,702 |
| Aug 15, 2026 | Evans Katie Seitz | See Remarks | Other | 11,204 | 24.73 | 277,075 |
| Aug 15, 2026 | Day David | CHIEF FINANCIAL OFFICER | Other | 14,170 | 24.73 | 350,424 |
| Aug 15, 2026 | Barrett Michael G. | CEO | Other | 10,404 | 24.73 | 257,291 |
| Aug 14, 2026 | Caine Paul | Director | Sell | 7,500 | 25.00 | 187,500 |
| Aug 13, 2026 | Day David | CHIEF FINANCIAL OFFICER | Other | 26,258 | 0.00 | – |
| Aug 10, 2026 | Gephart Brian | CHIEF ACCOUNTING OFFICER | Sell | 12,479 | 24.68 | 307,982 |
| Aug 10, 2026 | Lam Rachel | Director | Sell | 10,000 | 24.16 | 241,600 |
| Aug 10, 2026 | Caine Paul | Director | Sell | 5,000 | 24.35 | 121,750 |
| Aug 6, 2026 | Buonasera David | CHIEF TECHNOLOGY OFFICER | Sell | 871 | 25.00 | 21,775 |
| Aug 6, 2026 | Buonasera David | CHIEF TECHNOLOGY OFFICER | Sell | 2,602 | 24.00 | 62,448 |
| Aug 6, 2026 | Buonasera David | CHIEF TECHNOLOGY OFFICER | Sell | 4,176 | 22.81 | 95,255 |
| Aug 6, 2026 | Buckley Sean Patrick | See Remarks | Sell | 19,237 | 23.00 | 442,451 |
| Aug 6, 2026 | Buckley Sean Patrick | See Remarks | Sell | 47,942 | 25.09 | 1,202,865 |
| Aug 6, 2026 | Buckley Sean Patrick | See Remarks | Other | 28,703 | 13.90 | 398,972 |
| Aug 6, 2026 | Evans Katie Seitz | See Remarks | Sell | 20,000 | 24.00 | 480,000 |
| Aug 6, 2026 | Evans Katie Seitz | See Remarks | Other | 20,000 | 5.16 | 103,200 |
| Aug 6, 2026 | Knopper Douglas S | Director | Sell | 37,337 | 22.72 | 848,297 |
| Aug 6, 2026 | Barrett Michael G. | CEO | Sell | 293,968 | 22.72 | 6,678,953 |
| Aug 6, 2026 | Barrett Michael G. | CEO | Other | 293,968 | 5.80 | 1,705,014 |
| Jul 15, 2026 | Barrett Michael G. | CEO | Sell | 38,596 | 20.35 | 785,429 |
| Jul 15, 2026 | Barrett Michael G. | CEO | Other | 38,596 | 5.80 | 223,857 |
| Jul 10, 2026 | Caine Paul | Director | Sell | 5,000 | 20.64 | 103,200 |
| Jul 7, 2026 | Buonasera David | CHIEF TECHNOLOGY OFFICER | Sell | 1,224 | 21.00 | 25,704 |
| Jul 7, 2026 | Buckley Sean Patrick | See Remarks | Sell | 19,233 | 21.03 | 404,470 |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: September 18, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.