Ask a Fool: How Much of My Assets Should Be in Cash?
Generally speaking, cash is a poor investment choice. Not only do cash and equivalent investments generate small (if any) returns, but thanks to inflation, a stockpile of cash actually loses purchasing power over time.
However, there are a few exceptions.
First, everyone should have an emergency fund that is in readily accessible, cash-equivalent assets. Experts say that you should aim to save at least six months' worth of expenses in cash, in case of a job loss or major unexpected expense.
Source: Fool.com