Definition of 'Ring Fence'
A protection-based transfer of assets from one destination to another, usually through the use of offshore accounting. A ring fence is meant to protect the assets from inclusion in an investor's calculable net worth or to lower tax consequences.
Moves to ring fence an asset are often called "ring fence trades".
Investopedia explains 'Ring Fence'
There are many legal options available in many countries to ring fence assets, although many have caps that are set at a percentage of one's net worth. The main motivation for moving assets (or capital) into a ring fence is to free it from undue restrictions, tax burdens or other country-specific laws. Property or assets held outside a nation's jurisdiction cannot have claims brought on them, so they become "untouchable" by the investor's home country.