Big Four accounting firm Deloitte says the net worth of mega-rich families is expected to explode by trillions of dollars in the coming years.

In its Private's Family Office Insight Series, Deloitte projects ultra-rich families who manage their wealth through private offices will grow their fortunes from $5.5 trillion today to $9.5 trillion in 2030.

Dr. Rebecca Gooch, Deloitte Private's global head of insights, says the mega-wealthy are growing their fortunes at a blistering pace.

"Off the back of gains in their operating businesses and wider investments, the world's most affluent families have been accumulating wealth at a meteoric pace - and we expect this trend to continue."

According to the Deloitt, high-net-worth families in North America with family offices are projected to see their fortune rise by 258% from around $1.12 trillion in 2019 to $4 trillion in 2030.

Ultra-rich families in Asia Pacific are estimated to grow their wealth from about $650 billion to $2 trillion over the same time frame, a 208% climb.

Meanwhile, super-rich families in Europe are anticipated to grow their wealth from $1.1 trillion in 2019 to $2.8 trillion in 2030 for an increase of 157%.

Although there's no widely recognized amount of cash that makes a family ultra wealthy, ultra-High-Net-Worth Individuals (UHNWIs) are typically defined as people with investable assets of at least $30 million.