During his time, many a developer has soared and then crashed. If one thing has distinguished Walker, it's been his ability to sell out at the right time, or close to it, and come back to the party later. He's been as much a trader as an investor.

While the Walker empire is always open to deal, he has two major sell-downs on his corporate CV: In 1999 he sold his stake in the then-listed Walker Corporation to Australand – the dot-com bomb hitting the next year didn't damage him; and in 2006 he flogged a $1.25 billion portfolio to Mirvac – and his business kept growing through the GFC.

And now he's attempting his biggest sale ever – about $2.5 billion for Melbourne's Collins Square properties. There might be a lesson here somewhere.

I once asked Walker how he knew it was time to bail out ahead of the GFC. He said it was because the money being paid for property simply didn't make sense, he couldn't see how it could be developed and rented at a profit. He mentioned a particular competitor in the industrial space who seemed to be sending "kids with clipboards" to auctions paying more for land than the land could return. It wasn't hard to decide to sell down.

Walker now looks like taking advantage of mainly foreign buyers – from Canadian pension funds to Chinese billionaires - chasing prime CBD property in their global search for yield. And while they're searching and buying, they're pushing down the yields they seek.

For Lang Walker, it's another opportunity. For the Reserve Bank of Australia, it's an area of concern.

While most media have concentrated on speculating about residential real estate ("house price crash" seems to rival "Kardashian" and  "star's wardrobe malfunction" as click bait), the RBA is keeping an increasingly close eye on commercial lending.

That's not a surprise – it's been commercial real estate, not residential, that has been the source of Australian banks' biggest problems in the past.

In a speech earlier this month on The Risk Environment and the Property Sector, RBA assistant governor Malcolm Edey underlined that commercial property had been a common source of financial instability both here and overseas.

He said that while Australian banks remained in comparatively good shape during the GFC, they did suffer a noticeable rise in non-performing assets to nearly 2 per cent of all loans. Impaired commercial property accounted for about 30 per cent of those non-performing domestic assets. And then he issued his warning:

"The commercial property sector is again experiencing strong investor demand, and bank lending to the sector is increasing. However there are a number of signs of increasing risk.

"Trends in commercial property prices and rents have been diverging over the past few years, with prices continuing to rise while rents have been flat to down. As a result, yields have declined. At the same time, vacancy rates have been increasing.

"As in the housing market, conditions have not been uniform across the country, and they have been noticeably firmer in Sydney and Melbourne than in other centres. But in aggregate, the major categories of commercial property have all seen downward pressure on yields over recent years. Strong demand from foreign buyers has contributed to this, reflecting the global environment of low interest rates and 'search for yield'

"The risks appear manageable at this stage, but they underscore the need for sound lending practices and for appropriate prudence by investors."

Australian banks have learned to take a hint. Anecdotally, I'm told local bankers celebrate now when big commercial property is sold and they are repaid, not when they make a new loan.

Edey produced two graphs with data from JLL Research and Savills that demonstrated where the extra demand is coming from and the gap that has opened up between prices and rents.

The growth in foreign purchases of commercial property, especially office property, has been remarkable, while the divergence between the movement of prices and rents for CBD offices is becoming extraordinary – perhaps too extraordinary for Lang Walker.

I don't know what Walker's taste in music runs to, but you might suspect that someone in the party mix on his Kokomo superyacht is a little Kenny Rogers:

You've got to know when to hold 'em
Know when to fold 'em
Know when to walk away
And know when to run
You never count your money
When you're sittin' at the table
There'll be time enough for counting
When the dealin's done