ARM's chief technology Mike Muller officer has pocketed more than £2m from the sale of most of his stake in the designer of chips for mobile phones and other gadgets.
He offloaded 350,000 shares at just less than 580p a time, but still has a 1.11m shares in the company.
ARM's technology is used in computers, set top boxes and 'smartphones' such as the BlackBerry and the Palm Pre. Soaring consumer demand for such devices has been pushing ARM's profits - and share price - sharply higher.
Subscribe to MoneyWeek
Subscribe to MoneyWeek today and get your first six magazine issues absolutely FREE
The company last week said underlying fourth quarter profits jumped 47% to £47.6m from £32.3m, helping to lift the full year total by 73% to £167.4m.
"It is generally expected that, after a strong recovery in 2010, the semiconductor industry will see more typical growth levels in 2011. With ARM well positioned to continue to gain share, we expect group dollar revenues for the full-year to be at least in line with market expectations," chief executive Warren East said.
Mike Muller was one of the founders of ARM, which was founded in 1990 as a joint venture between Acorn Computers, where Muller used to work, and Apple.
Top Director Buys
Pursuit Dynamics (PDX) Director name: Mr Brian N C SweeneyAmount purchased: 5,450 @ 364.75p Value: £19,879
May Gurney Integrated Services (MAYG) Director name: Mr Andrew John WalkerAmount purchased: 7,500 @ 262.00p Value: £19,650
Top Director Sells
ARM Holdings (ARM) Director name: Mr Mike MullerAmount sold: 350,000 @ 579.94p Value: £2,029,790
Who is the richest person in the world?
The top five richest people in the world have a combined net worth of $825 billion. Who takes the crown for the richest person in the world?
By Vaishali Varu Published
Top 10 stocks with highest growth over past decade - from Nvidia, Microsoft to Netflix, which companies made you the most money?
We reveal the 10 global companies with the biggest returns since 2013. One firm has posted an astonishing 9,870% return, meaning a £1,000 investment would now be worth almost £82,000.
By Ruth Emery Published