It is also notable because it will bring down the curtain on one of the most remarkable - and inspiring - business careers since the war, not just in Australia, but anywhere.
For Sir Frank Lowy, the man who built Westfield, has declared that the sale will mark the moment when he retires.
The story of Sir Frank, who was knighted by the Queen at Windsor Castle last Friday, is also the story of post-war Australia.
:: Westfield shopping centres sold in £18.5bn deal
Born in 1930 in Filakovo, a town on the Slovak-Hungarian border, Sir Frank's family moved to Hungary when he was a child.
When the Nazis invaded Hungary, in 1944, Sir Frank's father, Hugo, immediately sought to buy rail tickets at Budapest station to get the family out.
He was arrested there and Sir Frank, who was 14 at the time, never saw him again.
He only discovered in 1991 that his father had been taken to the death camp at Auschwitz-Birkenau, where he had been beaten to death.
Sir Frank visited Auschwitz four years ago where in a speech on Holocaust Memorial Day, he revealed his father had been murdered for refusing to give up his prayer shawl and his tefillin, boxes worn by Orthodox Jewish men during weekday morning prayers.
In his biography, Pushing the Limits, Sir Frank recalled: "Once father was taken away, my childhood ended.
"My days were spent scheming how to live, eat and survive. I don't remember having any friends."
Sir Frank and his mother, Ilona, spent the rest of the war in a Budapest ghetto and after the war, he made his way to what is now Israel, fighting in the conflict that led to the country's formation as an independent state.
In 1952, as a penniless migrant and speaking little English, he arrived in Sydney, where his mother had already moved, getting a job as a delivery boy for a delicatessen owned by a fellow Hungarian called Jeno Schwarcz.
The pair went into partnership in 1953 to open a food store in Blacktown, a district of western Sydney many immigrants arriving in Australia had made their home, opening another shop in the same block inside a year as the local population grew rapidly.
After a brief dalliance with residential development, their next project was a department store with car parking spaces and the pair - Mr Schwarcz later changed his name to the Anglicised John Saunders - quickly realised that as in America, mass car ownership was about to become the norm in Australia, leading to the creation of big suburban shopping centres.
He recalled: "We saw what happened in the United States, the advent of urban sprawl, the cars, the parking, the merchandise, the new stores, supermarkets, it was all happening at that time. It was fascinating."
The company, named Westfield in 1956 in a reference to their location in western Sydney and the undeveloped land behind their original stores, opened its first mall in July 1959 in Blacktown and expanded rapidly thereafter.
The business floated on the stock market in June 1960 in order to access more capital and, by the early 1960s, was opening at least one mall a year.
Westfield's website points out that anyone who had invested A$1,000 at the flotation, kept their shares for the subsequent 50 years and reinvested all of their dividends, would have seen the value of that shareholding balloon to A$159m by the end of 2009.
It is no exaggeration to say Westfield brought modern shopping to Australia.
In 1968 and 1969, it expanded beyond New South Wales, opening its first malls in Queensland and Victoria, before taking its first steps overseas a decade later in the US.
In just over 10 years, it had seven US malls worth US$1.1bn.
Mr Lowy bought out Mr Saunders - who died 10 years later - in 1987 and continued to grow the business in both the US and Australia, expanding into New Zealand for the first time in 1997.
In 2000, it came to Britain for the first time, buying a centre in Nottingham.
This was followed in 2008 by the Westfield centre in Shepherd's Bush, west London.
By then Mr Lowy and his three sons, who had joined him in running the business, had actually been selling some assets ahead of the global financial crisis.
Steven, his middle son, explained: "We didn't foresee the credit crunch.
"But we asked how long things could go on being so good."
In 2012, in time for the London Olympics, Westfield Stratford - the biggest shopping centre in Europe - opened.
Two years later, the company was restructured, with its assets in Australia and New Zealand housed in a separate business called Scentre.
This remains listed on the Sydney stock exchange and Mr Lowy stepped down as its chairman last year.
Yet building a retail empire and accumulating an A$8.3bn fortune, as well as giving away hundreds of millions of dollars in good causes, is not Mr Lowy's only legacy.
He is also seen as the man who has done more than anyone to put football on the map in Australia where, until recent times, it was seen as a poor relation to rugby league, rugby union and Aussie rules.
As chairman of Football Federation Australia, a job he took at the behest of former Prime Minister John Howard, Mr Lowy oversaw an overhaul of the sport that saw it rebadged from 'soccer' to 'football' and set up the new A-League.
Clubs, which had traditionally been organised along racial or ethnic lines, were ordered to rebadge, for example, with South Melbourne dropping 'Hellas' from its name.
Australia chose to compete for World Cup qualification in Asia rather than Oceania and, in 2006, qualified for the tournament for the first time in 32 years.
What has marked Mr Lowy out has been a refusal to rest on his laurels.
He was irritated when the Australian Financial Review said Westfield had done well by sticking to its knitting, responding: "If I had stuck to my knitting, I would have had a wonderful career having a delicatessen in Blacktown.
"I probably would be the best delicatessen owner around.
"So you've got to test the envelope, find out what are your abilities and if you falter, pick yourself up and test it again. Otherwise, what is it all about, you know?"