Legendary investor Sir John Templeton once warned that the four most dangerous words for investors were: "This time it's different."
As share markets move up and down, investors are prone to using this rationale to justify emotion-driven decisions.
And the phrase has been heard more frequently of late, as investors grapple with what impact coronavirus, or Covid-19, will have on the global economy and the markets.
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Australian billionaire investor Hamish Douglass is one who believes the crisis will pass, and most likely go down in history as a severe flu rather than a global pandemic, albeit with unknown severity.
However, he does warn that there is an increasing probability of a black swan event such as a global pandemic with high mortality rates.
The founder of the Sydney-based Magellan Financial Group spoke to the Herald ahead of an investor roadshow in Auckland on Tuesday.
"We will in our lifetime get a true pandemic, which has high mortality rates and very big spread around the world. From what I can see today, this doesn't look like that," he said.
Douglass qualified his statement, saying the Covid-19 situation is still fluid, and the outbreak is likely to have significant short-term economic impacts at the very least.
"Most likely within three to six months, like a flu this will pass and ultimately we will have a pretty sharp economic recovery from whatever the consequences in the short term are."
Mike Morell, a former deputy head of America's Central Intelligence Agency who also presented at the Auckland event, agreed with that sentiment.
"I think that if I had to bet right now, it's going to end up to be a severe flu and not worse than that. We don't know what we don't know. But I think that's where it's heading," Morell told the Herald.
"At some point in time there will be a serious pandemic with a pathogen that spreads rapidly and kills people in large numbers. That will happen. It's almost guaranteed by biology. What I hope is that the coronavirus will get governments world-wide thinking about how do we prepare for such an event.
"Because most governments around the world don't think about it. I still don't think most governments are prepared. I know my government is not prepared.
"So I really hope this event galvanises people to say, okay, let's think about what it's going to take to deal with a true pandemic and let's get ready for it globally."
Douglass said Magellan's investment strategy was intertwined with global interest rates and if anything the central banks' response to the coronavirus was pushing markets deeper into a super low interest rate world.
Magellan recently surpassed A$100 billion in funds under management and has made the most of the 10-year bull market with strong returns for shareholders. Magellan's 10-year performance to June 30, 2019 was 16.28 per cent versus 11.95 per cent for the benchmark (in Australian dollar terms).
"The people who are saying the market needs a sharp correction are the people who are looking at the multiple of the market compared to historical averages and on that basis it appears the market is fully valued, if not over-valued and therefore needs a correction.
"But what people are missing in the context of that discussion is the market's multiple relative to interest rates. If these interest rates are to hold anywhere near this sort of level for an extended period of time, these markets are not expensive.
"If interest rates stay at 2 per cent or less, things are cheap in the world. But if they are at 4 per cent things are over-valued. And I feel quite confident on those two book-ends but then you have to think about which world we are entering into.
"The problem is in relation to the interest rate world - it may be different for a very long period of time."