I want to find out what is the possible rise in my portfolio after investing during crisis, and in so doing, I can find out the optimum amount of cash to keep. The problem with cash is that while it's very useful during crisis, there's a cost to it. It's the drag on your portfolio return, that is, your cash is rotting in the bank doing nothing. On the other hand, investing throughout the ups and downs will mean that your portfolio volatility will be swinging in extremes too. Not for the faint hearted. I start off by looking at Straits time index in the past. These are the major crisis that happened and what the STI returns look like after while. The first dates indicated the lowest point in STI while the second date refers to the apex of the bull run that occurs after market recovers. The % ......