Sydney real estate agent John McGrath has made many millions out of the city's booming property market over the past three decades.
The 52-year-old has built up a chain of highly successful real estate agencies worth hundreds of millions of dollars.
He is the author of motivational book You Don't Need To Be Born Brilliant and was a judge on entrepreneurial television show The Shark Tank.
But in the past week, McGrath has learned the stock market is a very different beast from the housing market.
Shares in his real estate business, which he listed on the stock market in December, crashed as the company downgraded its projected revenue by A$4 million ($4.5 million).
The company, which was valued at A$215 million, expects to sell fewer houses than it forecast in its prospectus, which will eat into its commission revenue.
It blamed a 25 to 30 per cent drop in sales activity in northwest Sydney and less activity from Chinese buyers.
What has really hurt the group was its purchase of the Smollen Group for A$52 million. This company owned the McGrath real estate agency franchises in northwest Sydney where the sales have fallen most sharply.
Even before the announcement, shares in McGrath were trading at about half of December's A$2.10 listing price and after the news broke they dropped to a low of A90c, before recovering to close last week at A$1.105.
Some brokers have slashed their earnings forecasts and share price targets on the company.
Bell Potter analyst Chris Savage now has a 12-month target price of A$1.50, down 33 per cent from a A$2.25 target price last week.
However, it is notable he still has a "buy" recommendation on the stock.
As you might expect from a master salesman, John McGrath remains confident. He acknowledges the housing market is cooling but says it won't collapse.
To his credit, McGrath has taken the opportunity of the share price fall to buy more shares.
Last Monday he spent about half a million dollars to snap up some shares at A90c each and now owns close to 30 per cent of the real estate sales company.
The McGrath float late last year was timed perfectly, at least for the sellers. The company was listed at the peak of the real estate market, just before house prices started coming off this year.
In fact, the median house price in Sydney has now dropped below A$1 million again.
McGrath got his big break in real estate when he was 24 and working for another estate agency.
He received a phone call from Perth asking him to sell a house in Sydney's upmarket harbourside Point Piper.
He achieved a then record price of A$11.2 million, which put him on the map and propelled him to start his own business.
The share price reaction highlights one of the key differences with the stock market - there is nowhere to hide. Bad news has to be made public and assets in the form of shares are repriced instantly.
With houses (and private companies) bad news can be kept out of the public eye and assets are only repriced when it's time to sell.
McGrath will have to get used to a whole new level of public scrutiny and investor expectations.
Riding not so high
And now to another business where the good times also couldn't last.
Shares in Qantas have slipped 20 per cent over the past week as the airline said there was less demand for its domestic flights and it would reduce the number of seats available.
The airline is blaming a drop in consumer confidence and the upcoming federal election.
Businesses often stop spending during elections, so with a mammoth campaign ahead of the July 2 election, we can expect to see other companies with downgraded forecasts.
Not only will Qantas sell fewer seats, it will be selling them for less. The average price of domestic airfares fell by 5.77 per cent in the first quarter of the calendar year, after having risen by 8 to 9 per cent last year when demand was stronger.
The airline says the drop off in demand is only temporary.
Maybe, but it highlights the key problem with aviation businesses (and indeed with investing in them).
They operate on very tight margins and there are so many things that can go wrong - fuel prices, a weak economy, global terrorism scares, disease outbreaks such as SARS, or an increase in competition from other airlines.
When any one of those things happen, good times quickly become bad times.
That's why it is so tough to make consistent profits out of aviation, as Qantas is demonstrating once again.