Rare event but if it occurs it seemed counter-intuitive to add to a section of the portfolio where forecasts might be falling. It seems what you are saying is that you should go with whatever your system tells you because this is still the best diversified portfolio?
You've created a trading system with the characteristics you want, given some amount of capital. You shouldn't change the trading system just because you have a different amount of capital.
What if the reverse were true? What if you were reducing your capital, but you had increasing forecasts in one part of your system? Would you act to increase your positions locally there; flying in the face of Kelly? I think the answer is no.
Of course there is a minor issue here - you might incur extra trading costs as a result of this conflicting behaviour, but the use of buffering will reduce these - and unless your vol target is insane trading due to capital changes will be dwarfed by vol and forecast changes.
GAT
