I made a few investments, and surprise, surprise, a few of them shot up in value. Now I'm faced with the dilemma of the greedy: do I sell now and capitalize on existing profits, or do I wait, risking my existing gains in the hopes of gaining more?
The optimal answer, intuitively at least, is somewhere in the middle. Sell some portion of your newly appreciated investment, capitalizing a little, but leaving some in the pot to hopefully grow. This sounds an awful lot like something there'd be a handy dandy formula for, maybe plug in a few values and you get a mathematically or game-theoretic optimal proportion of the position to sell off.
Does such a formula exist? Perhaps a few that fill this function?