Robert W. Duggan owns 76.47% of Summit Therapeutics
610,015,809 shares as of the June 12, 2026 filing, worth $8.9B at the latest close.
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Free.
The stake
76.47%
worth $8.9B at the latest close
Stake rank
#14
by dollar value of the stake
Last sale
None
no sales since 2020
Last buy
129 days ago
Jun 12, 2026 · $50M
Robert W. Duggan owns 76.47% of Summit Therapeutics Inc.: 610,015,809 of 797,749,602 shares, worth about $8.9B at the 2026-10-16 close. The stake has moved from 12.57% in 2020 to 76.47% on 2026-07-17, across 0 sales and 8 purchases that moved it since 2016. The last trade that moved it was a discretionary purchase of $50M on 2026-06-12.
How the stake is held
as of the Jun 12, 2026 filing
SHARES
OF THE STAKE
COMMON STOCK · stated Jun 12, 2026 · Form 4 ↗
HELD DIRECTLY
573,883,879
94.1%
HELD INDIRECTLY · 4 VEHICLES
36,131,930
5.9%
By the Mahkam Zanganeh Revocable Trust, with the Spouse of Reporting Person as Trustee
25,824,474
4.2%
By the Shaun Zanganeh Irrevocable Trust, with the Spouse of Reporting Person as Trustee
10,199,776
1.7%
Immediate family member of Spouse
76,680
0.0%
By Spouse
31,000
0.0%
THE STAKE
610,015,809
76.47%