Fortinet's Xie Brothers Sold $42M in Stock on the Same Day

Same Day, Same Playbook: $42M Combined

On February 2, 2026, both co-founders of Fortinet (FTNT) executed large stock sales on the same day. CEO Ken Xie sold roughly 175,700 shares for $14.3 million, while CTO Michael Xie sold approximately 343,100 shares for $28.0 million. Both brothers exercised options at a strike price of $16.90 per share and sold on the open market at $81–$82.

The simultaneous timing is notable but not unusual for related insiders operating under 10b5-1 pre-arranged trading plans. What is unusual is the career-long divergence between the two brothers’ selling habits.

Transaction Detail: February 1–2, 2026

Michael Xie (VP Engineering & CTO)

Date	Type	Shares	Price	Est. Value
Feb 1	Tax withholding (F)	18,975	$81.26	$1.5M
Feb 2	Exercise (M)	648,570	$16.90	—
Feb 2	Sell (S)	343,106	$81.01–82.28	$28.0M
Total net sell				$28.0M

Ken Xie (President & CEO)

Date	Type	Shares	Price	Est. Value
Feb 1	Tax withholding (F)	42,685	$81.26	$3.5M
Feb 2	Exercise (M)	269,760	$16.90	—
Feb 2	Sell (S)	175,737	$81.06–82.33	$14.3M
Total net sell				$14.3M

The $16.90 Options: 380% Spread

Both brothers exercised stock options with a strike price of $16.90 — grants dating back to Fortinet’s earlier years. With FTNT trading at $81–$82 on the exercise date, each option generated roughly $64 in profit, a 380% gain. Michael’s 648,570-share exercise alone netted an estimated $41.5 million in gross profit before taxes.

This exercise-and-sell pattern is their established playbook. Both brothers have been converting deep-in-the-money options into cash for over 15 years, since Fortinet’s November 2009 IPO.

The Divergence: $5.8B vs $223M

Here’s where it gets interesting. Despite nearly identical transaction counts (822 for Michael vs 721 for Ken), the career sell totals are wildly different:

• Michael Xie (CTO): $5.84 billion in total sales, $0 in purchases
• Ken Xie (CEO): $223 million in total sales, $500 in purchases

Michael has sold 26 times more stock than his brother despite holding a less prominent title. The implication: Michael has been systematically liquidating his founder stake for years, while Ken has retained the vast majority of his position. Ken still holds approximately 51.4 million shares worth an estimated $4.2 billion, making him one of the largest individual shareholders in the cybersecurity sector.

Michael’s remaining direct position of roughly 10.2 million shares (~$830M) is substantial but represents a fraction of what he has already sold.

Fortinet Context

Founded in 2000 by the Xie brothers, Fortinet has grown into one of the world’s largest cybersecurity companies. The brothers previously co-founded NetScreen Technologies, which Juniper Networks acquired for $4 billion in 2004. Fortinet went public in 2009 at a split-adjusted price below $5. The stock has returned over 1,500% since IPO.

The brothers’ coordinated selling activity has been a constant throughout Fortinet’s public history. Michael Xie alone has filed 822 Form 4 transactions — averaging one filing every 7 days for over 16 years. There have been zero open-market purchases from either brother.

What to Watch

• Ken’s retention — With 51.4M shares, Ken Xie holds roughly 6.5% of Fortinet’s outstanding shares. Any shift in his selling pattern would be a significant signal.
• Michael’s remaining stake — At 10.2M shares, Michael may have another $800M+ in remaining stock. His pace suggests continued selling through 2026.
• Gift activity — Michael gifted 245,000 shares in December 2025, suggesting charitable or estate planning alongside the sales program.
• Cybersecurity sector momentum — The sales come as the cybersecurity sector trades near all-time highs, adding context to the brothers’ timing.

Track both brothers’ insider transactions: Ken Xie (CEO) and Michael Xie (CTO). View institutional holders of Fortinet on the FTNT stock detail page.