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SMMTSummit Therapeutics Inc. · Insider ownership research

Summit Therapeutics Inc. insiders: what they own and what they did with it

None of it through sales. No officer or director reported an open-market sale in this period.

Updated Oct 13, 2026 from SEC filings · covers Oct 14, 2025 to Oct 13, 2026
3
buyers among officers and directors (6 trades), past 12 months
0 of 10
officers and directors sold shares, past 12 months
Is this normal? Less than usual: no sales, against a 5-year average of 15K shares a year. 0 insiders sold; the average is 0 a year. Year by year
Latest filing: Filed Jun 12 for a purchase on Jun 12. Robert Duggan bought 3.81M shares ($50.0M). Filing
SEC ownership filings: 19 filed in the 12 months to Oct 13, 2026; 129 on record since Sep 18, 2020 · See the evidence

What stands out

Three officers bought shares: Robert Duggan (3.91M shares, $51.4M), Mahkam Zanganeh (3.91M shares, $51.4M) and Manmeet Soni (50K shares, $722K).Robert Duggan: purchase, Jun 12, 2026 · Mahkam Zanganeh: purchase, Jun 12, 2026 · Manmeet Soni: purchase, Jun 4, 2026

No officer or director sold shares in this period. 10 are left out

i
Left out: Robert Duggan, Mahkam Zanganeh, Yu Xia, Manmeet Soni, Bhaskar Anand, Jeff Huber, Kenneth Clark, Robert Booth, Alessandra Cesano and Mostafa Ronaghi (share of stake is being verified).
Disclosed company stock is not an insider's whole wealth.

Recent activity

Past 30 days, Sep 14, 2026 to Oct 13, 2026

No officer or director trades were reported for the past 30 days. The most recent before that:

Jun 12, 20262 executives bought 7.62M shares ($100.0M).
WhoSharesPrice% of total stakeTotal stake afterTrade dateFiled
Robert Duggan
Co-Chief Executive Officer, Director
3,810,000$13.12n/an/aJun 12, 2026Jun 12, 2026
Mahkam Zanganeh
Co-Chief Executive Officer, Director
3,810,000$13.12n/an/aJun 12, 2026Jun 12, 2026

Common questions

Is the Summit Therapeutics Inc. CEO selling stock?

No. Robert Duggan reported no open-market sales in the past 12 months.

Are any Summit Therapeutics Inc. insiders buying?

Yes. 3 officers or directors reported 6 purchases in the past 12 months (Form 4 code P; rows the filings describe as reinvested dividends, plan purchases, private deals or moves into the person's own trust are not counted).

The evidence

The full ownership picture0 of 10 officers and directors confirmed

Vested shares across all share classes, held directly and through trusts, LLCs and family members, as reported on SEC Forms 3, 4 and 5. Unvested awards and options are never counted as owned shares.

InsiderHeld Oct 13, 2025SoldHeld Oct 13, 2026Still held
Robert Duggan
!
Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Robert Duggan are complete.
Co-Chief Executive Officer, Director
n/a0n/an/a
Vesting, gifts, unvested awards and holding lines for Robert Duggan

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Robert Duggan are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
10,724$18.35Jan 2, 2035$0
11,232$17.52Jan 2, 2036$0
203,323$3.71Nov 11, 2030$1.9M
2,400,000$4.40Nov 22, 2030$20.9M
15,000$4.75Dec 15, 2031$126K
11,988,198$1.68Oct 13, 2033$137M
260,000$1.06Jun 28, 2032$3.1M
100,000$1.29Sep 9, 2032$1.2M
2,397,640$1.68Oct 13, 2033$27.4M
9,590,558$1.68Oct 13, 2033$110M
1,040,000$1.06Jun 28, 2032$12.5M
400,000$1.29Sep 9, 2032$4.7M

Estimate: options held × ($13.12 − strike price), using the most recent insider trade price on Form 4 (Jun 12, 2026), not a market close.

Mahkam Zanganeh
!
Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Mahkam Zanganeh are complete.
Co-Chief Executive Officer, Director
n/a0n/an/a
Vesting, gifts, unvested awards and holding lines for Mahkam Zanganeh

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Mahkam Zanganeh are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
11,988,198$1.68Oct 13, 2033$137M
260,000$1.06Jun 28, 2032$3.1M
100,000$1.29Sep 9, 2032$1.2M
2,397,640$1.68Oct 13, 2033$27.4M
9,590,558$1.68Oct 13, 2033$110M
1,040,000$1.06Jun 28, 2032$12.5M
400,000$1.29Sep 9, 2032$4.7M
10,724$18.35Jan 2, 2035$0
11,232$17.52Jan 2, 2036$0

Estimate: options held × ($13.12 − strike price), using the most recent insider trade price on Form 4 (Jun 12, 2026), not a market close.

Yu Xia
!
Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. See the filing Sales and other transactions for Yu Xia are complete.
Director
n/a0n/an/a
Vesting, gifts, unvested awards and holding lines for Yu Xia

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Yu Xia are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
235,000$2.64Jan 2, 2034$2.5M
35,000$18.35Jan 2, 2035$0
5,438$18.35Jan 2, 2035$0
35,000$17.52Jan 2, 2036$0

Estimate: options held × ($13.12 − strike price), using the most recent insider trade price on Form 4 (Jun 12, 2026), not a market close.

Manmeet Soni
!
Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Manmeet Soni are complete.
COO and CFO, Director
n/a0n/an/a
Vesting, gifts, unvested awards and holding lines for Manmeet Soni

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Manmeet Soni are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
14,000,000$1.68Oct 13, 2033$160M
1,100,000$3.85Apr 2, 2034$10.2M
2,800,000$1.68Oct 13, 2033$32.0M
11,200,000$1.68Oct 13, 2033$128M

Estimate: options held × ($13.12 − strike price), using the most recent insider trade price on Form 4 (Jun 12, 2026), not a market close.

Bhaskar Anand
!
Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Bhaskar Anand are complete.
Chief Accounting Officer
n/a0n/an/a
Vesting, gifts, unvested awards and holding lines for Bhaskar Anand

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Bhaskar Anand are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
600,000$3.85Apr 2, 2034$5.6M
75,000$17.85Jan 12, 2035$0
600,000$3.85Apr 2, 2034$5.6M
75,000$17.85Jan 12, 2035$0
50,000$19.23Sep 18, 2035$0
30,000$18.83Jan 8, 2036$0

Estimate: options held × ($13.12 − strike price), using the most recent insider trade price on Form 4 (Jun 12, 2026), not a market close.

Jeff Huber
!
Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Jeff Huber are complete.
Director
n/a0n/an/a
Vesting, gifts, unvested awards and holding lines for Jeff Huber

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Jeff Huber are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
217,883$7.87Jun 27, 2034$1.1M
35,000$18.35Jan 2, 2035$0
35,000$17.52Jan 2, 2036$0
9,885$17.52Jan 2, 2036$0

Estimate: options held × ($13.12 − strike price), using the most recent insider trade price on Form 4 (Jun 12, 2026), not a market close.

Kenneth Clark
!
Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Kenneth Clark are complete.
Director
n/a0n/an/a
Vesting, gifts, unvested awards and holding lines for Kenneth Clark

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Kenneth Clark are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
105,492$2.64Jan 2, 2034$1.1M
200,000$19.95Oct 11, 2034$0
35,000$18.35Jan 2, 2035$0
16,991$18.35Jan 2, 2035$0
35,000$17.52Jan 2, 2036$0
17,796$17.52Jan 2, 2036$0

Estimate: options held × ($13.12 − strike price), using the most recent insider trade price on Form 4 (Jun 12, 2026), not a market close.

Robert Booth
!
Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Robert Booth are complete.
Director
n/a0n/an/a
Vesting, gifts, unvested awards and holding lines for Robert Booth

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Robert Booth are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
82,651$2.64Jan 2, 2034$866K
35,000$18.35Jan 2, 2035$0
6,855$18.35Jan 2, 2035$0
35,000$17.52Jan 2, 2036$0
7,180$17.52Jan 2, 2036$0

Estimate: options held × ($13.12 − strike price), using the most recent insider trade price on Form 4 (Jun 12, 2026), not a market close.

Alessandra Cesano
!
Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Alessandra Cesano are complete.
Director
n/a0n/an/a
Vesting, gifts, unvested awards and holding lines for Alessandra Cesano

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Alessandra Cesano are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
56,363$2.64Jan 2, 2034$591K
35,000$18.35Jan 2, 2035$0
3,073$18.35Jan 2, 2035$0
35,000$17.52Jan 2, 2036$0
3,219$17.52Jan 2, 2036$0

Estimate: options held × ($13.12 − strike price), using the most recent insider trade price on Form 4 (Jun 12, 2026), not a market close.

Mostafa Ronaghi
!
Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Mostafa Ronaghi are complete.
Director
n/a0n/an/a
Vesting, gifts, unvested awards and holding lines for Mostafa Ronaghi

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Mostafa Ronaghi are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
225,315$4.03Apr 11, 2034$2.0M
35,000$18.35Jan 2, 2035$0
35,000$17.52Jan 2, 2036$0

Estimate: options held × ($13.12 − strike price), using the most recent insider trade price on Form 4 (Jun 12, 2026), not a market close.

Holdings and share of stake for Summit Therapeutics Inc. are being verified, so no balances, unit counts or percentages are shown. Sales, proceeds, plan and tax status, titles and dates come straight from individual filings.

Is this normal? Selling year by year5 earlier years to compare with

Less than usual: no sales, against a 5-year average of 15K shares a year. 0 insiders sold; the average is 0 a year.

12 months endingShares soldInsiders who soldProceeds
Oct 13, 2026
Latest 12 months
00$0
Oct 13, 2025
1 year earlier
00$0
Oct 13, 2024
2 years earlier
00$0
Oct 14, 2023
3 years earlier
00$0
Oct 14, 2022
4 years earlier
00$0
Oct 14, 2021
5 years earlier
74K1$321K

Open-market sales (Form 4 code S) by people who were officers or directors, in split-adjusted shares. Earlier years include people who have since left. A sale that an outside holder also reports (a family trust, a fund) is counted with outside holders in every year. Shares, not dollars, are compared, so a change in the stock price doesn't look like a change in selling. Years the filings don't fully cover are shown but left out of the average.

Known gaps and uncertainty10 officers and directors not confirmed

Holdings and share of stake are being verified. Balances, unit counts and every share-of-stake figure for Summit Therapeutics Inc. are held back until that check is finished. Sales, proceeds, plan and tax status, titles and dates come straight from individual filings and are complete.

External context: we only cite outside events when a documented connection exists. None is shown for this period.

Sources and methodology129 filings on record, 19 filed in the 12-month period, and how we read them

All 129 Forms 3, 4 and 5 on record for Summit Therapeutics Inc. (SEC CIK 1599298), filed from Sep 18, 2020 to Jun 12, 2026; 19 of them were filed in the 12 months this page covers, retrieved from SEC EDGAR on Oct 13, 2026. Prices are the ones reported in each filing, often weighted averages.

Holdings. Each holding line (a share class plus an owner, such as a trust or LLC) carries its last reported balance forward. Entities first reported during the period start at zero, so transfers between an insider's own trusts don't count as selling. Lines not reported for three years or more are listed separately and left out of totals.

Sales. A sale counts as under a 10b5-1 plan if its footnote cites one or the filing's Rule 10b5-1 box is checked, and as tax-related if its footnote cites tax obligations or sell-to-cover. Shares withheld by the company for taxes are listed separately. Sales with neither attribute are labeled "no plan disclosed".

Full methodology

Former or inactive filers (11)No filing in 18 months; last reported balances, not in any total
NameLast filedLast reported balance
Ankur DhingraMar 27, 2024394,485 shares, last reported balance as of Mar 26, 2024
Ujwala MahatmeJan 4, 2024No balance on record
Urte GaykoApr 26, 2022No balance on record
Jeffrey MaranianDec 17, 2021No balance on record
Luhua WangMar 2, 2021No balance on record
Michael DonaldsonFeb 23, 2021No balance on record
Rainer ErdtmannFeb 23, 2021No balance on record
David PowellDec 1, 2020No balance on record
Camilla GrahamOct 7, 2020No balance on record
Ventzislav StefanovSep 18, 202014,900 shares, last reported balance as of Sep 18, 2020
Jos HoubiersSep 18, 202015,512 shares, last reported balance as of Sep 18, 2020

Spotted something wrong on this page? Report an error. We check every report against the SEC filing and list what we fix in the corrections log.