Intercom, the customer messaging software company that McCabe (34) and Traynor (37) founded along with Ciaran Lee and David Barrett in 2011, became Ireland's first tech unicorn last March, achieving a valuation of just over €1bn.
It's thought that while both have converted some of their equity into cash in recent years, the four founders have carefully held on to about half of the company between them.
The firm - which employs over 400 people split between Dublin, London, San Francisco, New York, Chicago and Sydney - is believed to have revenues of about €45m and over 25,000 paying customers, which includes corporate giants such as IBM and Microsoft.
Its backers include some of Silicon Valley's biggest VC firms and entrepreneurs, including Ireland's very own fellow Rich Listers, the billionaire Collison brothers, who founded Stripe.
The two Dubliners are also recycling their money into angel investments in other tech startups such as Productboard, Front, Mobilize and Digit.