A bare 0.004% of the world's adult population controls nearly $30 trillion in assets, 13% of the world's total wealth, according to a new study today. 

The study by the Swiss bank UBS and luxury industry consultant Wealth-X also said the concentration of money in the hands of the ultra-rich is growing. 

The report said 211,275 people qualify as "ultra-high net worth" (UHNW) - those with assets above $30m. Of them, 2,325 have more than $1 billion. 

Their numbers grew 6% over the past year, but their wealth grew 7%, as asset markets like stocks and property soared in many places around the world. 

The fastest growth, indeed, came in the "demi-billionaire" group worth a half-billion to a billion dollars each, the study said. 

Even amidst geopolitical conflicts, socio-economic strife, and volatile currency markets, the world's equity markets displayed strong performances, thereby enabling UHNW individuals' wealth to increase and their influence across industries and sectors to grow - from their importance in wealth management to their consumption of luxury goods," the study said. 

"Such a large concentration of wealth in the hands of these few individuals means that they tend to have a large degree of influence, whether on global equity markets or specific industries," it added. 

Of the nearly $30 trillion this elite group controls, just over one-third is in the hands of tycoons in North America, more than one-quarter in Europe, and 23% in Asia. 

Of them, 87% are men, with an average age of 59, and nearly one-quarter of them were in banking. Of them, 68% were "self-made" rich, 13% rich by inheritance, and the rest a combination of the two. 

The average ultra-rich woman was 57, and more likely to be involved in non-profit and social organisations (19%) than any other sector. Nearly half became wealthy through inheritance, while one-third were self-made wealthy. 

The average UHNW-er spends $1m a year on luxury goods and services. Yet, the study points out, luxury items can be "part and parcel of their lifestyle and are not necessarily considered a 'luxury.'" 

"For example, UHNW individuals with private jets use their aircraft not only for leisure, but also for business purposes. On the other hand, while yachts, and particularly superyachts, are usually a non-necessity, many UHNW individuals lead very public lives, and the privacy of a family holiday on a yacht is a very special treat," it added.