[grey-area]

I have an alternative explanation for you which is much simpler and in their interests.

Cash is more liquid than assets and since in the short term inflation is a mild penalty and there is negligible return for risk free assets any more (nor are they as risk free as before), they keep large proportions in cash for the short term while waiting for assets that present a good return.

It is entirely rational to hold some proportion of wealth cash for the short term.