The Affluent Luxury Living Index, compiled by Stonehage, which advises ultrawealthy families, illustrates that prices for the most expensive goods and services are much more volatile than the standard rate of inflation. "When times are good high net worth individuals are generally not very cost conscious," said Ronnie Armist, executive director at Stonehage Investment Partners.

"But when there is an economic downturn, everyone feels the need to tighten their belt, including HNW individuals."

The basket of components that makes up the alternative inflation index for the wealthy shows some wide variations in inflation, however, giving an insight into how different parts of the luxury sector are faring.