SEI Investments’s Magnite MGNI Stock Holding History

SEI Investments’s Portfolio MGNI Stock Details MGNI Fund Activity

Bought

Maintained

Sold

Quarter	Market Value	Status	Shares	Change in Stake	Trade Value	Portfolio Weight	Portfolio Position
2026 Q2	$3.14M	Sell	165,553 -185,309	-53%	-$2.65M	﹤0.01%	1724
2026 Q1	$4.17M	Buy	350,862 +139,325	+66%	+$1.87M	﹤0.01%	1644
2025 Q4	$3.43M	Buy	211,537 +136,554	+182%	+$2.27M	﹤0.01%	1565
2025 Q3	$1.63M	Sell	74,983 -7,133	-9%	-$168K	﹤0.01%	1779
2025 Q2	$1.98M	Buy	82,116 +42,353	+107%	+$624K	﹤0.01%	1658
2025 Q1	$454K	Sell	39,763 -6,406	-14%	-$102K	﹤0.01%	2180
2024 Q4	$735K	Buy	46,169 +21,464	+87%	+$315K	﹤0.01%	2056
2024 Q3	$342K	Buy	+24,705	New	+$337K	﹤0.01%	2305
2023 Q3	–	Sell	-27,466	Closed	-$375K	–	2661
2023 Q2	$375K	Buy	27,466 +6,367	+30%	+$70.9K	﹤0.01%	2242
2023 Q1	$195K	Buy	21,099 +9,010	+75%	+$96K	﹤0.01%	2486
2022 Q4	$128K	Buy	+12,089	New	+$110K	﹤0.01%	2418
2022 Q3	–	Sell	-42,681	Closed	-$379K	–	2696
2022 Q2	$379K	Buy	+42,681	New	+$457K	﹤0.01%	2218
2021 Q4	–	Sell	-22,696	Closed	-$633K	–	2634
2021 Q3	$633K	Sell	22,696 -101,839	-82%	-$3.06M	﹤0.01%	1962
2021 Q2	$4.21M	Buy	124,535 +52,636	+73%	+$1.78M	0.01%	1171
2021 Q1	$2.99M	Buy	+71,899	New	+$3.11M	0.01%	1282
2020 Q3	–	Sell	-185,025	Closed	-$1.23M	–	2468
2020 Q2	$1.23M	Sell	185,025 -20,456	-10%	-$128K	﹤0.01%	1469
2020 Q1	$1.14M	Buy	205,481 +121,692	+145%	+$1.12M	﹤0.01%	1413
2019 Q4	$684K	Sell	83,789 -32,003	-28%	-$263K	﹤0.01%	1800
2019 Q3	$1.01M	Buy	115,792 +51,243	+79%	+$449K	﹤0.01%	1603
2019 Q2	$411K	Sell	64,549 -34,010	-35%	-$209K	﹤0.01%	1993
2019 Q1	$599K	Buy	+98,559	New	+$507K	﹤0.01%	1801
2017 Q4	–	Sell	-58	Closed	–	–	3423
2017 Q3	$0	Buy	+58	New	+$247	﹤0.01%	3315

Other funds holding MGNI

BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return

Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM

Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return

Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM

Wellington Management Group Boston, Massachusetts $580B AUM 38.23% 1-Year Est. Return

Dimensional Fund Advisors Austin, Texas $552B AUM 44.19% 1-Year Est. Return

Boston Partners Boston, Massachusetts $113B AUM 38.87% 1-Year Est. Return

American Century Companies Kansas City, Missouri $226B AUM 44.75% 1-Year Est. Return

Capital Research Global Investors Los Angeles, California $717B AUM 35.42% 1-Year Est. Return

Nuveen Charlotte, North Carolina $419B AUM 43.02% 1-Year Est. Return

SEI Investments's MGNI Position: Q2 2026 in Review

SEI Investments reduced its Magnite (MGNI) stake by 53% in Q2 2026, selling an estimated $2.65M and leaving 165,553 shares worth $3.14M. The position accounts for ﹤0.01% of the portfolio, ranked #1724.

SEI Investments first reported a position in MGNI in Q3 2017 and has held it in 22 quarters since. The position peaked at $4.21M in Q2 2021. 311 funds tracked by Wall St. Rank hold MGNI as of Q2 2026.

SEI Investments held 165,553 shares of Magnite worth $3.14M as of Q2 2026.
SEI Investments sold 185,309 Magnite shares in Q2 2026, an estimated $2.65M.
Magnite made up ﹤0.01% of SEI Investments's portfolio in Q2 2026, its #1724 holding.
SEI Investments first reported a position in Magnite in Q3 2017 and has held it in 22 quarters since.
SEI Investments's Magnite position peaked at $4.21M in Q2 2021.
311 funds tracked by Wall St. Rank held Magnite as of Q2 2026.

Based on SEI Investments's 13F filing for Q2 2026, filed 14 Aug 2026.