The extraordinary nature of the property portal market took an unexpected twist this week when a 30-year-old Australian hedge fund manager told an audience in London that his firm is investing more than it has ever done before in a single firm – US portal Zillow.

It is doing so because it believes that it can hike advertising rates massively.

Shares in Zillow, which is in the process of merging with previous arch rival Trulia – the equivalent of Rightmove and Zoopla announcing marriage banns in the UK – immediately shot up by 5% in price on the back of his remarks.

Michael Messara, of Caledonia, said that his firm has invested in an “extraordinary opportunity” – putting in three times the investment it has ever made before into a single firm.

And the reason for the hedge fund’s biggest ever bet?

According to Messara, it is because what has been seen with property portals in both the UK and Australia.

The US property portal industry did not take off until 2005, much later than the UK, mainly because of the scattered and cottage industry nature of the US real estate industry.

Since then, however, 72% of US mobile property searches now take place on Zillow.

It has “unassailable” first-mover advantage.

Yet US agents currently spend just 4% of their advertising money on Zillow, suggesting that it is failing to monetize itself properly.

Currently, advertising revenue lags 72% market share by 18 times.

According to Messara, once a leader is established, it is all but impossible to knock them off their perch: he said that in all markets, the top two property portals have 70-80% of the market.

Messara said Zillow would follow the path of property portal markets in both Australia and the UK – where, in both, agents are challenging the established portals with offerings of their own.

It noted that Zillow has an excellent management team and very good IT, particularly with mobile devices.

Well, it certainly sounds as though US agents will be paying a lot more.

But it also begs some questions.

Will US agents decide to launch their own mutual challenger in a few years’ time?

Is it even faintly possible that in the UK, Rightmove and Zoopla could merge?

And just how likely is it that Agents’ Mutual can – as the man said – knock the top two off their perches.

These are interesting times.