Insider buying report — Wednesday, September 30, 2026: 55 open-market buys worth $353.9M
On Wednesday, September 30, 2026 the SEC published 55 open-market insider purchases worth $353.9M across 41 companies, against 21 insider sales of $1M or more worth $231.0M. Insiders were net buyers by dollar value.
The largest purchase
Conifer Management, L.L.C. (10% owner) at GROUP 1 AUTOMOTIVE INC (GPI) filed the day's largest purchase: 273,712 shares at $242.15, $66.3M in total, transacted on Sep 28, 2026 and filed Sep 30, 2026. What makes it notable: it is the largest purchase this insider has ever filed; the stock was at least 25% below its recent high when they bought.
Behind it: 667, L.P. at KOD ($63.4M), 667, L.P. at KOD ($58.6M), Berkshire Hathaway Inc at LEN ($53.9M).
Top ten insider buys
| Filed | Insider | Company | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| 2026-09-30 | Conifer Management, L.L.C.diplargest ever 10% owner | GPI GROUP 1 AUTOMOTIVE INC | Bought | 273,712 | $242.15 | $66.3M |
| 2026-09-30 | 667, L.P.largest ever Director · 10% owner | KOD Kodiak Sciences Inc. | Bought | 715,592 | $88.59 | $63.4M |
| 2026-09-30 | 667, L.P.largest ever Director · 10% owner | KOD Kodiak Sciences Inc. | Bought | 807,840 | $72.57 | $58.6M |
| 2026-09-30 | Berkshire Hathaway Incdip 10% owner | LEN LENNAR CORP /NEW/ | Bought | 660,410 | $81.59 | $53.9M |
| 2026-09-30 | 667, L.P. Director · 10% owner | KOD Kodiak Sciences Inc. | Bought | 418,323 | $83.58 | $35.0M |
| 2026-09-30 | Life Insurance Co Nipponlargest ever 10% owner | CRBG Corebridge Financial, Inc. | Bought | 805,782 | $34.15 | $27.5M |
| 2026-09-30 | Orbimed Advisors Llccluster Director · 10% owner | ADRX ADARx Pharmaceuticals, Inc. | Bought | 950,000 | $17.00 | $16.1M |
| 2026-09-30 | Carl L Gordoncluster Director · 10% owner | ADRX ADARx Pharmaceuticals, Inc. | Bought | 950,000 | $17.00 | $16.1M |
| 2026-09-30 | Ramin Kamfarclusterdiplargest ever Director | BPRE Bluerock Private Real Estate Fund | Bought | 425,590 | $12.57 | $5.4M |
| 2026-09-30 | Nechmad YairCEOchairdip CEO, Co Founder & Chairman | NYAX Nayax Ltd. | Bought | 46,935 | $44.90 | $2.1M |
Showing 10 of 55 open-market purchases filed on 2026-09-30. The full list, sortable and filterable by role and size, is in the members Filings Browser; the same rows are available as JSON through the API.
Signals in the day's buying
Of the purchases filed: 7 purchases by a chief executive (BCDA, CULP, FLNA, GPUS, KWY, NYAX); 3 by a CFO (ANIX, KWY, MNSO); 20 that belong to an active cluster (ADRX, AFCG, ANIX, BBD, BPRE, DTIL); 26 first-ever purchases by the insider; 29 bought at least 25% below the recent high. These are the flags the members area scores on — a CFO buying with their own money has historically been the strongest single-insider signal, and a cluster of three or more buyers the strongest of all. The cluster guide explains the scoring.
GPI — two years of insider activity on the price
KOD — two years of insider activity on the price
LEN — two years of insider activity on the price
Largest insider sales ($1M and up)
| Filed | Insider | Company | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| 2026-09-30 | Mallick Dhiraj Chief Operating Officer | CBRS Cerebras Systems Inc. | Sold | 395,402 | $204.02 | $80.7M |
| 2026-09-30 | Hsing Michael CEO | MPWR MONOLITHIC POWER SYSTEMS, INC. | Sold | 29,274 | $1,345.36 | $39.4M |
| 2026-09-30 | David A Duffield 10% owner | WDAY Workday, Inc. | Sold | 84,867 | $188.96 | $16.0M |
| 2026-09-30 | BCP Buzz Holdings L.P. 10% owner | BMBL Bumble Inc. | Sold | 3,454,135 | $2.94 | $10.1M |
| 2026-09-30 | BSOF Buzz Aggregator L.L.C. 10% owner | BMBL Bumble Inc. | Sold | 3,454,135 | $2.94 | $10.1M |
The largest sale was Mallick Dhiraj at Cerebras Systems Inc. (CBRS), $80.7M. Sales are shown from $1M upward only; below that they are overwhelmingly scheduled 10b5-1 plans and tax-driven, and listing them would bury the signal.
Context: the market-wide picture
For the week starting Sep 21, 2026, 33% of open-market insider filings across the whole market were buys (227 buys against 457 sales). The long-run average sits near a third, because insiders buy for one reason and sell for many. The full weekly series since 2019 is on the insider sentiment index.
Questions this post answers
Which insiders bought stock on Sep 30, 2026?
55 open-market purchases were filed with the SEC on Sep 30, 2026, worth $353.9M across 41 companies. The largest was Conifer Management, L.L.C. at GROUP 1 AUTOMOTIVE INC (GPI), $66.3M. The ten largest are listed above.
Were insiders net buyers or net sellers on Sep 30, 2026?
By dollar value, buyers: $353.9M bought against $231.0M in sales of $1M or more. Selling normally dominates because executives sell on pre-set schedules; what matters is the buying, which is voluntary.
What counts as an insider buy here?
Only Form 4 transactions with code P — an open-market purchase paid for with the insider's own money. Grants (A), option exercises (M) and shares withheld for tax (F) are excluded, because they follow vesting schedules set years earlier and say nothing about what the insider thinks of the price.
How current is this?
The SEC publishes Form 4 filings through about 10 pm Eastern each business day. This report covers everything published on Sep 30, 2026 and was generated early the next morning from the same data the members area uses.