A Form 4 is filed within two business days of a company insider — an officer, a director, or a holder of more than ten percent of the stock — changing their position in the shares. All 6 filings in this group are Form 4s for Summit Therapeutics Inc.
The difficulty with reading these filings as a group is that a single form type covers transactions that mean entirely different things. An executive spending their own money to buy stock and an executive having shares withheld to pay tax on a vesting grant both appear as a Form 4. Every filing below is therefore tagged with the nature of the underlying transaction, taken from the transaction code reported on the form itself.
Across the 6 insider filings shown, the breakdown is 5 open-market purchase and 1 compensation award. 5 of them involved a discretionary open-market trade; the rest are compensation and administrative mechanics.
Form 4
Compensation award
Tax / Compensation Filing
2026-10-14
SMMT insider Form 4 filed for equity award, exercise, or tax withholding
Anand Bhaskar (Chief Accounting Officer) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.
Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.
Transactions reported on this filing
| Code |
Nature |
Shares |
Price |
Value |
A |
Compensation award
|
100,000 |
— |
— |
Filing: Form 4 (Insider Transaction)
Insider: Anand Bhaskar (Chief Accounting Officer)
Shares: 100,000
Form 4
Open-market purchase
Insider Buying
2026-06-12
SMMT insider Zanganeh Mahkam (Director, Co-Chief Executive Officer, 10% Owner) bought 3,810,000 shares (~$49.99M)
Zanganeh Mahkam, listed as Director, Co-Chief Executive Officer, 10% Owner at Summit Therapeutics Inc., reported an open-market purchase of 3,810,000 SMMT shares in a Form 4 filing. Insider buying is often treated as a bullish signal because company insiders are committing their own capital.
The insider bought shares on the open market with their own money. This is the only Form 4 category that requires a discretionary cash outlay at the prevailing price.
Transactions reported on this filing
| Code |
Nature |
Shares |
Price |
Value |
P |
Open-market purchase
|
3,810,000 |
$13.12 |
$49.99M |
Filing: Form 4 (Insider Transaction)
Insider: Zanganeh Mahkam (Director, Co-Chief Executive Officer, 10% Owner)
Shares: 3,810,000
Est. Value: $49.99M
Form 4
Open-market purchase
Insider Buying
2026-06-12
SMMT insider DUGGAN ROBERT W (Director, Co-Chief Executive Officer, 10% Owner) bought 3,810,000 shares (~$49.99M)
DUGGAN ROBERT W, listed as Director, Co-Chief Executive Officer, 10% Owner at Summit Therapeutics Inc., reported an open-market purchase of 3,810,000 SMMT shares in a Form 4 filing. Insider buying is often treated as a bullish signal because company insiders are committing their own capital.
The insider bought shares on the open market with their own money. This is the only Form 4 category that requires a discretionary cash outlay at the prevailing price.
Transactions reported on this filing
| Code |
Nature |
Shares |
Price |
Value |
P |
Open-market purchase
|
3,810,000 |
$13.12 |
$49.99M |
Filing: Form 4 (Insider Transaction)
Insider: DUGGAN ROBERT W (Director, Co-Chief Executive Officer, 10% Owner)
Shares: 3,810,000
Est. Value: $49.99M
Form 4
Open-market purchase
Insider Buying
2026-06-04
SMMT insider DUGGAN ROBERT W (Director, Co-Chief Executive Officer, 10% Owner) bought 100,000 shares (~$1.46M)
DUGGAN ROBERT W, listed as Director, Co-Chief Executive Officer, 10% Owner at Summit Therapeutics Inc., reported an open-market purchase of 100,000 SMMT shares in a Form 4 filing. Insider buying is often treated as a bullish signal because company insiders are committing their own capital.
The insider bought shares on the open market with their own money. This is the only Form 4 category that requires a discretionary cash outlay at the prevailing price.
Transactions reported on this filing
| Code |
Nature |
Shares |
Price |
Value |
P |
Open-market purchase
|
100,000 |
$14.60 |
$1.46M |
Filing: Form 4 (Insider Transaction)
Insider: DUGGAN ROBERT W (Director, Co-Chief Executive Officer, 10% Owner)
Shares: 100,000
Est. Value: $1.46M
Form 4
Open-market purchase
Insider Buying
2026-06-04
SMMT insider Zanganeh Mahkam (Director, Co-Chief Executive Officer, 10% Owner) bought 100,000 shares (~$1.46M)
Zanganeh Mahkam, listed as Director, Co-Chief Executive Officer, 10% Owner at Summit Therapeutics Inc., reported an open-market purchase of 100,000 SMMT shares in a Form 4 filing. Insider buying is often treated as a bullish signal because company insiders are committing their own capital.
The insider bought shares on the open market with their own money. This is the only Form 4 category that requires a discretionary cash outlay at the prevailing price.
Transactions reported on this filing
| Code |
Nature |
Shares |
Price |
Value |
P |
Open-market purchase
|
100,000 |
$14.60 |
$1.46M |
Filing: Form 4 (Insider Transaction)
Insider: Zanganeh Mahkam (Director, Co-Chief Executive Officer, 10% Owner)
Shares: 100,000
Est. Value: $1.46M
Form 4
Open-market purchase
Insider Buying
2026-06-04
SMMT insider Soni Manmeet Singh (Director, COO and CFO) bought 50,000 shares (~$722.2K)
Soni Manmeet Singh, listed as Director, COO and CFO at Summit Therapeutics Inc., reported an open-market purchase of 50,000 SMMT shares in a Form 4 filing. Insider buying is often treated as a bullish signal because company insiders are committing their own capital.
The insider bought shares on the open market with their own money. This is the only Form 4 category that requires a discretionary cash outlay at the prevailing price.
Transactions reported on this filing
| Code |
Nature |
Shares |
Price |
Value |
P |
Open-market purchase
|
25,000 |
$14.46 |
$361.5K |
P |
Open-market purchase
|
25,000 |
$14.43 |
$360.8K |
Filing: Form 4 (Insider Transaction)
Insider: Soni Manmeet Singh (Director, COO and CFO)
Shares: 50,000
Est. Value: $722.2K