AS-4 Decline in the value of investment

Investments referred in AS4 are non current investments, & if you remember / know non-current investments are always carried at historical cost. 

reason behind carring long term investments at historical cost may be that in long term price/ market value is less volatile.

if doubt persist, contact any expert.

thank u.

there is 1 more thing though circumstances existing on balance sheet date , it will be difficult to prove that those circumstances will result in declining in value of investments for long term.