SMMT

Summit Therapeutics Inc.

Healthcare Pharmaceutical Preparations Market cap: $12.4B All insider activity → Quote and statistics → Sign in to watch SMMT Sign in to set a price alert

AI summary Top executives make multi-million dollar open-market purchases of Summit Therapeutics stock.

Insider Score Band 80+

Research score: 76
AI adjustment: +5

Research score, not a recommendation.

Total bought$103.6M6 Form 4 purchases

Distinct insiders3open-market buyers

Lead insiderZanganeh MahkamCEO

Cluster window2026-06-04 → 2026-06-12active

Market data

Live quote and chart from Yahoo Finance, loaded through this server. Insider purchases are marked on the chart.

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Why this score

Research score: a weighted blend of the five factors, times the routine and offering discounts, minus the selling penalty.

Breadth number & diversity of participating insiders

37%

Seniority executive rank of buyers (CEO/CFO/Director)

100%

Commitment purchase size relative to company & holdings

83%

Context buying into stock weakness signals conviction

85%

Timing coordinated purchases within a tight window

99%

Routine-purchase discount × 1.00

Company-type / offering discount × 1.00

Net insider selling penalty − 0

Why are they buying?

AI · discretionary · catalyst none · documented

The executives made large open-market share purchases without an explicit reason or immediate operational catalyst stated in the filings.

CEO Robert W. Duggan, co-CEO Mahkam Zanganeh, and CFO Manmeet Singh collectively acquired millions of dollars worth of common stock through open-market transactions in early June 2026.

Filing references and sources

Stock Price & Insider Purchase History

Daily close price with open-market insider purchases plotted over time

Loading price history…

Transactions

6 Form 4 trades · 3 insiders Sign in to download CSV

Purchases in this cluster, grouped by insider, largest first
Date	Insider	Role	Shares	Price	Value	Filing
2026-06-04 → 2026-06-12	Zanganeh Mahkam 8 purchases with a 63-day result · median +18.1%	CEO	3,910,000	$13.16 avg	$51.4M
2026-06-04	Zanganeh Mahkam		100,000	$14.60	$1.5M	SEC filing for Zanganeh Mahkam (opens in a new tab)
2026-06-12	Zanganeh Mahkam		3,810,000	$13.12	$50.0M	SEC filing for Zanganeh Mahkam (opens in a new tab)
2026-06-04 → 2026-06-12	DUGGAN ROBERT W 5 purchases with a 63-day result · median +16.7%	CEO	3,910,000	$13.16 avg	$51.4M
2026-06-04	DUGGAN ROBERT W		100,000	$14.60	$1.5M	SEC filing for DUGGAN ROBERT W (opens in a new tab)
2026-06-12	DUGGAN ROBERT W		3,810,000	$13.12	$50.0M	SEC filing for DUGGAN ROBERT W (opens in a new tab)
2026-06-04	Soni Manmeet Singh history of Soni Manmeet Singh's purchases	CFO	50,000	$14.45 avg	$722.2K
2026-06-04	Soni Manmeet Singh		25,000	$14.43	$360.8K	SEC filing for Soni Manmeet Singh (opens in a new tab)
2026-06-04	Soni Manmeet Singh		25,000	$14.46	$361.5K	SEC filing for Soni Manmeet Singh (opens in a new tab)
Total					$103.6M

Other buying runs at SMMT

A run ends after a pause in the buying, so one company can have several. Returns are the stock's return minus its benchmark's (IWM for small companies, SPY otherwise), from the first open after the run became a cluster. Past results, not a forecast.

After this run became a cluster: 21 days +3.6%63 days +12.9%126 days –

Other insider buying runs at this company, newest first, with the return against the benchmark that followed
Window	Insiders	Total	Score	21 days	63 days	126 days	Status
2025-10-21	3	$11.0M	71	-9.1%	-23.1%	+1.2%	closed
2023-03-06 → 2023-03-08	3	$437.8M	76	+3.0%	+16.7%	-1.0%	closed
2022-08-16	3	$97.7M	78	+13.4%	-17.0%	+78.5%	closed