The insatiable appetite of US investors for Irish commercial property is a source of both relief and puzzlement.

There is relief because they are providing a market for the National Asset Management Agency, which still has another €18 billion or so worth of property loans to unload. The puzzlement is because the value so apparent when the first US investors arrived in Dublin is getting harder and harder to discern.

Given that US corporations are involved, tax no doubt tax plays its part – in particular, the incentive introduced in 2011 under which property bought between December 2011 and December 2014 gets a seven-year holiday from capital gains tax. However, to avail of the relief the purchaser has to hold on to it for the seven years.

Michael Noonan (pictured) said on budget day the measure will not be extended. This should ensure the market puts in a strong last quarter this year. What happens after that and the impact on Nama's sales is harder to predict.

Equally difficult to gauge is the long tail effect on the market. The more bullish commentators hope that, as Nama winds down over the next few years, the market will get a second wind when investors start to split up the portfolios they have been buying from Nama.

The buyers for these properties are expected to be the locals who have been squeezed out by international players.

Post-Christmas market However, the prospect of giving up a seven-year tax holiday may cool the ardour of tax-driven overseas investors for slicing and dicing. What is for sure is that if the market cools after Christmas and the overseas buyers decide to hang on to their tax breaks, there will be calls for the extension or modification of the relief. That has a sadly familiar ring to it.