The cost of running a family office stood at an average of $11.4m over the last year, which includes $6.7m spent on operational costs and $4.7m on external investment management and administration fees.

Lucky then that these investment vehicles for the ultra wealthy have seen their strongest return in five years, according to a report released on Tuesday by UBS and Campden Wealth Research.

The average family office portfolio returned 15.5% in 2017, over double the amount from the previous year, notes The Global Family Office Report.

Though these returns eclipse an increase in running costs – caused by investment manager administration and performance fees – family office ownership remains outside the reach of all but the wealthiest UHNWIs.

The cost of running a family office CEO rose 11% over the year to $333,000, and that’s just their average base salary. In Europe, family office CEOs took home an average of $469,000, before a 29% proportionate bonus.

A shortage of family office talent can explain the salary increases. Last year 10 relationship managers left Morgan Stanley’s Asia’s private banking unit to join family offices. Asia-Pacific is the most expensive region to run a family office.

The Report notes that just 9% of these roles are held by women, though changes are afoot: 14% of family offices now have diversity targets in place.

Another significant area of spend is the average $203,000 spent on family governance and succession planning. 43% of family offices now have a succession plan, though Sara Ferrari, head of UBS’s Global Family Office Group thinks this is not enough: “Families need to be much more proactive in tackling the issue of succession.”

Private bankers see opportunities in this expenditure. The Report finds that 67% of family offices outsource private banking services. Global custody, reporting functions and concierge services are also areas where family offices seek external support.