He Ran Symantec and Chaired Microsoft. Now John Thompson Sells $600K in Rubrik Stock Every Month.

John W. Thompson has one of the most unusual insider trading records in corporate America. Over two decades, the veteran tech executive has filed 2,034 Form 4 transactions across seven public companies — from running Microsoft’s board as Chairman to selling $227 million in Rubrik’s predecessor Symantec. Now, at 76, he’s executing a textbook monthly liquidation of his Rubrik stake: convert shares, sell roughly $600,000, repeat on the first business day of every month.

His career total: $228 million in sales and $16 million in purchases across SYMC, MSFT, RBRK, UPS, NiSource, Seagate, and Illumina.

The Monthly Rubrik Machine

Since Rubrik’s IPO in April 2024, Thompson has executed the same pattern on the first trading day of every month: convert 9,009 Class B shares to Class A, then sell them at market. The amounts vary only with Rubrik’s stock price.

Date	Shares Sold	Avg Price	Proceeds
Mar 2, 2026	13,500	$53.30	$723K
Dec 1, 2025	9,009	$69.02	$619K
Nov 3, 2025	9,009	$75.55	$680K
Oct 1, 2025	9,009	$83.07	$746K
May 1, 2025	9,009	$71.45	$644K
Apr 1, 2025	9,009	$60.19	$542K
Mar 3, 2025	9,009	$63.18	$569K
Feb 3, 2025	9,009	$70.98	$639K
Jan 14, 2025	9,009	$64.70	$583K

The March 2026 sale broke the pattern slightly: Thompson exercised 11,000 options at $4.38 per share (his original pre-IPO strike price) and sold 13,500 shares rather than the usual 9,009. At $53 per share, he netted roughly $723,000 — the options exercise alone representing a 1,100% return on paper.

The Seven-Company Trail

What makes Thompson’s filing record remarkable is its breadth. Most insiders file at one or two companies. Thompson spans seven:

Company	Ticker	Role	Period	Transactions	Shares Bought	Shares Sold
Symantec	SYMC	CEO & Chairman	2003–2011	1,688	325,000	10,214,119
Microsoft	MSFT	Chairman	2012–2023	135	23,194	0
Rubrik	RBRK	Director	2024–present	101	0	121,608
UPS	UPS	Director	2003–2013	87	17,921	3,584
NiSource	NI	Director	2003–2005	18	0	0
Seagate	STX	Director	2004–2010	10	0	0
Illumina	ILMN	Director	2018–2022	5	0	0

The contrast between Microsoft and Symantec is striking. At Symantec, where Thompson served as CEO, he sold over 10 million shares — essentially his entire compensation over eight years. At Microsoft, where he served as the independent Chairman who helped select Satya Nadella as CEO in 2014, he never sold a single share. All 135 Microsoft transactions were stock awards that he held.

The Symantec Chapter: $227 Million

Thompson joined Symantec as CEO in 1999, following a 28-year career at IBM. During his tenure, he transformed Symantec from a consumer antivirus company into an enterprise security giant through the $13.5 billion acquisition of Veritas Software in 2005. He stepped down as CEO in 2009 and remained Chairman until 2011.

Throughout this period, Thompson filed 1,688 transactions — overwhelmingly sales. He sold 10.2 million shares, bought 325,000, and collected $227 million in proceeds. Symantec was later acquired by Broadcom in 2019 for $10.7 billion, validating the enterprise pivot Thompson engineered.

Why Rubrik Matters Now

Rubrik went public in April 2024 at $32 per share, raising $752 million. The cybersecurity and data protection company has since grown its revenue to over $900 million annually, though it remains unprofitable. Thompson holds a pre-IPO stake through trusts, with approximately 845,000 indirect shares as of late 2025.

His monthly selling pattern is consistent with a 10b5-1 pre-arranged trading plan — the same mechanism used by most corporate insiders to avoid timing questions. At the current pace of ~9,000 shares per month, his indirect holdings would take roughly 7-8 years to fully liquidate.

Institutional holders of Rubrik include Vanguard Group and BlackRock, both of which hold significant positions in the cybersecurity company.

Key Facts

Metric	Value
Career transactions	2,034 across 7 companies
Career sells	$227.5 million
Career buys	$15.9 million
Companies filed at	SYMC, MSFT, RBRK, UPS, NI, STX, ILMN
Microsoft shares sold	Zero
Rubrik monthly cadence	~9,009 shares on 1st business day
RBRK option strike	$4.38 (pre-IPO)
Current RBRK holdings (indirect)	~845,000 shares
Full profile	View all transactions

What to Watch

• Rubrik’s next monthly conversion — Thompson’s 9,009-share sell on the first business day of April 2026 will signal whether the pattern continues or the March acceleration (13,500 shares) becomes the new baseline.
• Rubrik lockup and vesting schedules — As a pre-IPO board member, Thompson’s remaining ~845K indirect shares vest on a rolling schedule. Monitor whether conversion sizes increase as more tranches unlock.
• Microsoft board composition — Thompson stepped down as Chairman in 2021 but may still hold unvested awards. Any future MSFT Form 4 filing would be the first sale in his 11-year history with the company.
• Illumina board activity — Thompson served on Illumina’s board through the contentious Grail acquisition battle. Any new filings would signal re-engagement with the genomics company.
• Trust restructuring pace — Thompson holds Rubrik shares across multiple entities. The January 2026 conversion of 55,000 shares between trusts suggests ongoing estate planning that may change the selling cadence.