It's universally known as "the race that stops a nation". But here's proof it really does.
Data from the Commonwealth Bank, supplied to news.com.au, shows card transactions plummeted on Tuesday during the race as Australians, quite literally, stopped spending and started watching.
CommBank figures showed credit and debit card transactions dropped 33 per cent between 3pm and 3.05pm - when the Cup was on. The drop was even steeper from 2.55pm to 3.05pm, at 38 per cent.
Spending on transport, however, peaked to coincide with key race times.
Taxi and Uber usage spiked initially at midday, up 65 per cent on the same day and time last week, which was in the midst of Halloween.
Once safely deposited at their racecourse, restaurant or pub of choice, Australians then stayed put for hours. Between noon and 3pm, taxi and Uber transactions fell 37 per cent.
It shot up again at 7pm, up 52 per cent on the same day the previous week, and up 96 per cent from the drop at 3pm on Melbourne Cup Day, as inebriated racing fans crawled home, desperate to get enough sleep to avoid a hangover at work the next day.
Commonwealth Bank executive Pete Steel said Melbourne Cup has always been a very unique day payments-wise.
"We don't see a consistent trend like this on any other day of the year - where spending drops off dramatically during an exact moment in time.
"Our transaction data shows a steady increase in activity throughout the morning, peaking at 1pm, followed by a sharp fall when the horses jump at 3pm. For the five minutes between the start of the race and when the winner is announced - transactions drop off significantly," Steel said.
"Once the race is over, we're back spending, but there is a steady decline for the rest of the afternoon, which is pretty consistent with the drop-off at the end of a normal day."
But although Australia might be spending less at certain times of the day, the organisers of the Cup insist that, overall, Australia is quids in.
The Victoria Racing Club (VRC) says the carnival contributed A$427.1 million ($473.6m) in gross economic benefit to the state last year; a 16.6 per cent increase since 2012.
"The Melbourne Cup Carnival is a resounding success story. This is Australia's original major event and it contributes to the economy like no other," club chairwoman Amanda Elliott said.
"Such a sizeable economic benefit filters right through the economy, and especially to sectors such as tourism, retail and fashion, hospitality and accommodation, supporting jobs across the state."
The club said A$44.3m is spent on fashion and retail in Victoria because of the cup. That includes 49,067 pairs of new shoes, 46,448 dresses, 11,659 suits and 59,665 hats and fascinators.
Almost $24m is spent on meals, food and beverages, and $45.2m on betting.