So the argument is that putting some of the money in stocks will make the trust fund more profitable and avoid, or at least put off, the day it runs out of money.
It is argued that putting some of the money in stocks will make the trust fund more profitable. 
mnli hypothesis: It is argued that putting some of the money in stocks will make the trust fund more profitable.  premise: So the argument is that putting some of the money in stocks will make the trust fund more profitable and avoid, or at least put off, the day it runs out of money.