Insider Selling on September 30, 2026: CBRS, BMBL and MPWR Lead $268.5M of Sales

Company insiders filed 55 open-market sales worth $268.5M with the SEC on September 30, 2026, across 43 companies. 35 of them (64%) were made under Rule 10b5-1 plans set up months in advance, which makes a sale less telling. Below are the largest, with what each insider owns now, how the stock has moved since, and each company's insider trading over the past 90 days.

The 15 largest insider sales filed Sep 30

Unscheduled sales

The largest sales made outside Rule 10b5-1 plans by officers and directors rather than 10% owners. These are the sales worth reading.

• Doehner Cobian Mauricio (EVP Corporate Affairs) at CX sold 927,900 shares at $9.57 ($8.9M), cutting their holding 61%.
• Adamo Claudine (Executive Vice President) at COST sold 2,200 shares at $915.93 ($2.0M), cutting their holding 24%.
• Moore Richard H (Chief Executive Officer, Director) at FBNC sold 23,343 shares at $62.85 ($1.5M), cutting their holding 22%.
• Mcnamara Kevin J (president and CEO, Director) at CHE sold 2,000 shares at $513.45 ($1.0M), cutting their holding 2.9%.
• Frates Caton (Sr. Executive Vice President) at COST sold 801 shares at $915.93 ($733K), cutting their holding 9.2%.
• Stocchi Mauro (See Remarks) at STVN sold 13,649 shares at $21.50 ($293K), cutting their holding 3.3%.
• Montgomery Charles D (Director) at APT sold 21,943 shares at $5.04 ($111K), cutting their holding 46%.
• Li Na (CFO and Director, Director) at LHAI sold 30,000 shares at $1.50 ($45K), their entire reported stake.

Biggest stake cuts

The sales that shrank an insider's holding the most, in percent.

• Mallick Dhiraj (Chief Operating Officer) at CBRS sold 396,000 shares at $204.04 ($80.8M), their entire reported stake.
• Wang Xiaodong (Director, Chair, Scientific Advisory Brd) at ONC sold 31,028 shares at $364.79 ($11.3M), their entire reported stake.
• Komin Robert Patrick Jr. (Chief Financial Officer) at CBRS sold 32,500 shares at $203.53 ($6.6M), their entire reported stake.
• Silbermann Benjamin (Director, 10% Owner) at PINS sold 93,750 shares at $18.53 ($1.7M), their entire reported stake.
• Atay Oguzhan (Chairman and CEO, Director) at BLLN sold 10,999 shares at $120.64 ($1.3M), their entire reported stake.
• Li Na (CFO and Director, Director) at LHAI sold 30,000 shares at $1.50 ($45K), their entire reported stake.

Cerebras Systems Inc. (CBRS)

Mallick Dhiraj (Chief Operating Officer) sold 396,000 shares starting Sep 29 at an average $204.04, about $80.8M. They sold their entire reported stake. The trade was made under a Rule 10b5-1 plan set up in advance. Read the Form 4.

Komin Robert Patrick Jr. (Chief Financial Officer) sold 32,500 shares starting Sep 29 at an average $203.53, about $6.6M. They sold their entire reported stake. The trade was made under a Rule 10b5-1 plan set up in advance. Read the Form 4.

Patel Yagnesh (Chief Accounting Officer) sold 1,320 shares starting Sep 28 at an average $204.50, about $270K. That cut their holding 7.9%, leaving 15,356 shares. The trade was made under a Rule 10b5-1 plan set up in advance. Read the Form 4.

CBRS last closed at $115.16 on Oct 29, -43.5% from the average sale price. Since Aug 1, Cerebras Systems Inc. insiders filed 0 open-market purchases ($0) and 15 sales ($387.7M). 84 13F filers hold CBRS among their 50 largest positions, including Brad Gerstner, Gavin Baker and Philippe Laffont.

Who traded CBRS since Aug 1:

• Lie Sean (Chief Technology Officer): 4 sales of 921,257 shares, about $192.1M
• Mallick Dhiraj (Chief Operating Officer): 2 sales of 434,889 shares, about $89.4M
• Feldman Andrew D. (CEO, President, Director): 3 sales of 301,644 shares, about $61.1M
• Vassallo Steven (Director): 2 sales of 100,000 shares, about $21.4M
• Vishria Eric (Director): 1 sale of 68,268 shares, about $15.7M
• Komin Robert Patrick Jr. (Chief Financial Officer): 1 sale of 32,500 shares, about $6.6M
• Patel Yagnesh (Chief Accounting Officer): 2 sales of 5,894 shares, about $1.3M

See every CBRS insider trade and which funds own CBRS.

Bumble Inc. (BMBL)

BX Buzz ML-1 GP LLC (10% Owner) sold 3,767,776 shares starting Sep 28 at an average $2.94, about $11.1M. That cut their holding 99.6%, leaving 16,120 shares. Read the Form 4.

Blackstone Holdings III GP Management L.L.C. (10% Owner) sold 3,767,776 shares starting Sep 28 at an average $2.94, about $11.1M. That cut their holding 99.6%, leaving 16,120 shares. Read the Form 4.

Btoa - Nq L.L.C. (10% Owner) sold 3,767,776 shares starting Sep 28 at an average $2.94, about $11.1M. That cut their holding 99.6%, leaving 16,120 shares. Read the Form 4.

2 more insider filings for BMBL came in the same day.

BMBL last closed at $5.98 on Oct 29, +103.5% from the average sale price. Since Aug 1, Bumble Inc. insiders filed 0 open-market purchases ($0) and 5 sales ($55.4M). 4 13F filers hold BMBL among their 50 largest positions, including Boaz Weinstein.

Who traded BMBL since Aug 1:

• BX Buzz ML-1 GP LLC (10% Owner): 1 sale of 3,767,776 shares, about $11.1M
• Blackstone Holdings III GP Management L.L.C. (10% Owner): 1 sale of 3,767,776 shares, about $11.1M
• Btoa - Nq L.L.C. (10% Owner): 1 sale of 3,767,776 shares, about $11.1M
• BCP Buzz Holdings L.P. (10% Owner): 1 sale of 3,767,776 shares, about $11.1M
• BX Buzz ML-1 Holdco L.P. (10% Owner): 1 sale of 3,767,776 shares, about $11.1M

See every BMBL insider trade.

Monolithic Power Systems, Inc. (MPWR)

Hsing Michael (CEO, Director) sold 30,000 shares starting Sep 28 at an average $1,344.97, about $40.3M. That cut their holding 3.5%, leaving 818,264 shares. The trade was made under a Rule 10b5-1 plan set up in advance. Read the Form 4.

MPWR last closed at $1,198.81 on Oct 29, -10.9% from the average sale price. Since Aug 1, Monolithic Power Systems, Inc. insiders filed 0 open-market purchases ($0) and 7 sales ($40.7M). 118 13F filers hold MPWR among their 50 largest positions, including Torray Funds and Dan Sundheim. Members of Congress disclosed 7 trades in MPWR over the past year; most recently Tommy Tuberville (R-AL) sold $1,001–$15,000 on May 3.

Who traded MPWR since Aug 1:

• Hsing Michael (CEO, Director): 1 sale of 30,000 shares, about $40.3M
• Dean Robert W II (Interim CFO): 3 sales of 143 shares, about $191K
• Chang Kuo Wei Herbert (Director): 2 sales of 100 shares, about $135K
• Sciammas Maurice (EVP, WW Sales & Marketing): 1 sale of 30 shares, about $40K

See every MPWR insider trade and which funds own MPWR.

Workday, Inc. (WDAY)

Duffield David A (10% Owner) sold 98,971 shares starting Sep 28 at an average $188.55, about $18.7M. That cut their holding 48.5%, leaving 105,049 shares. The trade was made under a Rule 10b5-1 plan set up in advance. Read the Form 4.

WDAY last closed at $195.46 on Oct 29, +3.7% from the average sale price. Since Aug 1, Workday, Inc. insiders filed 0 open-market purchases ($0) and 7 sales ($130.3M). 64 13F filers hold WDAY among their 50 largest positions, including Al Gore and David Blood, First Eagle Investment Management and Arnold Van Den Berg. Members of Congress disclosed 16 trades in WDAY over the past year; most recently Gilbert Ray Cisneros, Jr. (D-CA) bought $1,001–$15,000 on Aug 18.

See every WDAY insider trade and which funds own WDAY.

BeOne Medicines Ltd. (ONC)

Wang Xiaodong (Director, Chair, Scientific Advisory Brd) sold 31,028 shares starting Sep 28 at an average $364.79, about $11.3M. They sold their entire reported stake. The trade was made under a Rule 10b5-1 plan set up in advance. Read the Form 4.

ONC last closed at $371.56 on Oct 29, +1.9% from the average sale price. Since Aug 1, BeOne Medicines Ltd. insiders filed 0 open-market purchases ($0) and 8 sales ($113.0M). 20 13F filers hold ONC among their 50 largest positions.

Who traded ONC since Aug 1:

• Oyler John (Chief Executive Officer, Director): 1 sale of 240,810 shares, about $86.5M
• Wang Xiaodong (Director, Chair, Scientific Advisory Brd): 2 sales of 69,315 shares, about $24.7M
• Lee Chan Henry (SVP, General Counsel): 2 sales of 3,710 shares, about $1.3M
• Rosenberg Aaron (Chief Financial Officer): 1 sale of 1,157 shares, about $362K
• Wu Xiaobin (President and COO): 1 sale of 280 shares, about $106K
• Ball Titus B. (Principal Accounting Officer): 1 sale of 132 shares, about $47K

See every ONC insider trade.

Cemex Sab De CV (CX)

Doehner Cobian Mauricio (EVP Corporate Affairs) sold 927,900 shares on Sep 30 at an average $9.57, about $8.9M. That cut their holding 61.3%, leaving 584,930 shares. Read the Form 4.

CX last closed at $10.83 on Oct 29, +13.2% from the average sale price. Since Aug 1, Cemex Sab De CV insiders filed 1 open-market purchase ($6.9M) and 2 sales ($11.2M). 24 13F filers hold CX among their 50 largest positions, including George Soros and Howard Marks. Members of Congress disclosed 1 trade in CX over the past year; most recently Sheri Biggs (R-SC) sold $1,001–$15,000 on Mar 18.

Who traded CX since Aug 1:

• Doehner Cobian Mauricio (EVP Corporate Affairs): 1 sale of 927,900 shares, about $8.9M
• Zambrano Lozano Rogelio (Director): 1 purchase of 400,800 shares, about $6.9M
• Elizondo de la Garza Oscar Balmore (VP of Global Ent. Services): 1 sale of 212,680 shares, about $2.3M

See every CX insider trade and which funds own CX.

BioNTech SE (BNTX)

Sahin Ugur (Chief Executive Officer, 10% Owner) sold 66,000 shares starting Sep 29 at an average $98.19, about $6.5M. That cut their holding 23.6%, leaving 214,209 shares. The trade was made under a Rule 10b5-1 plan set up in advance. Read the Form 4.

BNTX last closed at $89.13 on Oct 29, -9.2% from the average sale price. Since Aug 1, BioNTech SE insiders filed 0 open-market purchases ($0) and 10 sales ($63.7M). 19 13F filers hold BNTX among their 50 largest positions.

See every BNTX insider trade and which funds own BNTX.

CrowdStrike Holdings, Inc. (CRWD)

Kurtz George (PRESIDENT AND CEO, Director) sold 20,000 shares starting Sep 28 at an average $258.20, about $5.2M. That cut their holding 0.3%, leaving 7,571,504 shares. The trade was made under a Rule 10b5-1 plan set up in advance. Read the Form 4.

CRWD last closed at $261.15 on Oct 29, +1.1% from the average sale price. Since Aug 1, CrowdStrike Holdings, Inc. insiders filed 0 open-market purchases ($0) and 35 sales ($321.7M). 590 13F filers hold CRWD among their 50 largest positions, including Hamilton Helmer, David Shaw and Jim Simons. Members of Congress disclosed 6 trades in CRWD over the past year; most recently Gilbert Ray Cisneros, Jr. (D-CA) bought $1,001–$15,000 on Jul 17.

Who traded CRWD since Aug 1:

• Podbere Burt W. (CHIEF FINANCIAL OFFICER): 3 sales of 521,504 shares, about $135.0M
• Kurtz George (PRESIDENT AND CEO, Director): 25 sales of 529,065 shares, about $117.1M
• Watzinger Gerhard (Director): 1 sale of 120,000 shares, about $28.6M
• Austin Roxanne S (Director): 1 sale of 50,000 shares, about $11.9M
• Sentonas Michael (PRESIDENT): 1 sale of 49,863 shares, about $11.6M
• Gandhi Sameer K (Director): 2 sales of 40,000 shares, about $8.5M
• Davis Cary (Director): 1 sale of 29,940 shares, about $7.4M
• Saha Anurag (CHIEF ACCOUNTING OFFICER): 1 sale of 7,016 shares, about $1.6M

See every CRWD insider trade and which funds own CRWD.

Every number here comes from the original Form 4 filings. See all of the day's trades in the Sep 30 insider recap, or screen every Form 4 in the insider screener.