In normal times, the pressure on decision-makers to act is constant. Grappling through this extraordinary time, this pressure is clearly all the greater. For investors tossed violently by wrenchingly volatile markets, it’s arguably greater than ever. But investment success is not a positive function of activity. In fact, given the unavoidable cost of trading, an inverse relationship is more probable. More importantly, the decision to do nothing can often prove to be the most profitable decision of all. Nassim Taleb captures this insight characteristically well in his book, ‘Anti-Fragile: Things That Gain from Disorder’: ‘There is a Latin expression festina…