Clouds are hovering over New York’s housing market. A couple of years ago, property prices were spiralling ever higher — much like the new luxury skyscrapers now springing up in midtown Manhattan.

But estate agents say that sales volumes in the first quarter of 2018 were at their lowest level for six years. Meanwhile the median price per square foot was 18 per cent lower than a year earlier, according to some reports.

That leaves Manhattan estate agents nervously gossiping about the local outlook. However, it should prompt investors and policymakers to ask a bigger question: could New York’s jitters herald declines in other non-US real estate markets too? Do those global markets, in other words, display “ synchronicity ”, or spillover effects?