Not entirely sure we are talking cash assets here.
Very few organisations be it plc or trade union bodies have significant cash on deposit as this is a poor use of resources.
There is a certain chap down on an airfield close to the M23 that allegedly has a 2billion pounds trust fund and by definition this makes him a billionaire. The fact is that the fund can be used as security for borrowing so one would never actually know the true equity of the trust fund.
UNITE may have assets declared at £161million but this does not tell the whole story. If one were to view it from an accounting stand point then one would have to consider the liabilities secured on the assets.