And close to A$3b has been lost from the value of their shares this month alone.
While many Aussie rich-listers were affected by the stock market plunge, Atlassian suffered the biggest losses, with stock dropping by up to 7 per cent yesterday.
But if you were thinking about taking up a collection for the duo — think again.
Because despite the fall, they still have a healthy A$6.07b worth of stock each — or A$12.14b in total — compared to their combined net worth of A$14.2b before the most recent plunge.
The 38-year-olds have also still smashed the previous Young Rich List wealth record, which they held themselves, of A$6.08b.
The rise and fall of their net worth comes after both Sydney men dropped eye-watering sums on prestige real estate recently.
Last year, Farquhar shelled out A$71m for Point Piper mansion Elaine, where he now lives with wife Kim Jackson and their three young children.
That eye-watering price tag set the record for Australia's priciest property sale at the time.
But just last month, Cannon-Brookes toppled that hefty record after reportedly paying "close to A$100mn" for the historic Fairwater mansion, located right next door to Elaine.
But according to The Australian, Farquhar and Cannon-Brookes were not the only high-profile Australians to lose staggering amounts yesterday.
Billionaires James Packer, Andrew Forrest and Michael Heine all lost hundreds of millions as their share portfolio plummeted.
Meanwhile, Melbourne property developer Tim Gurner — the man who made headlines last year after saying young Aussies would struggle to buy a home when they were "spending A$40 a day on smashed avocados and coffees and not working" — has taken out the third spot on the 2018 rich list, with wealth of A$631m.
Ori Allon, who built his A$539m wealth in technology and property, scored fourth place, while equal fifth and sixth went to fitness entrepreneur Kayla Itsines and her fiance Tobi Pearce.
Itsines, 27, and her 26-year-old partner have amassed a combined A$486m fortune thanks largely to their fitness app, Sweat.
Subscribers forking out A$19.95 each month in exchange for fitness and meal plans, shopping lists and exercise advice.
Itsines is now officially Australia's richest young woman, and the Adelaide couple are also the wealthiest self-made 20-somethings in the country.
Seventh place goes to Owen Kerr, with A$460m to his name thanks to his stake in foreign exchange Brokerage Company Pepperstone.
Husband-and-wife duo Collis and Cyan Ta'eed, who founded online graphic marketplace Envato, are jointly worth A$428m, earning them the eighth and ninth places, while farming and finance capital investor Peter Greensill sits in 10th place with A$412m in the bank.
