"Black Swan" encapsulates in a ballet the improbable arrival of the rare bird — and event that's become a source of great concern to companies.
I just came across this Booz & Co. white paper by Matthew Le Merle, a partner in the firm's San Francisco office. Titled "Are You Ready for a Black Swan? Stress-Testing the Enterprise with Disrupter Analysis," it expands on Nassim Nicholas Taleb's book, "The Black Swan," in which Taleb outlined the dreaded black-sawn event. In a nutshell, a black swan shocking and impactful, but — and this is a big but — it's rationalized after the fact. If we had known X,Y,Z, we could have seen it coming.
The general assumption is that black swans are rare. At one point in human history, people weren't sure black swans even existed. However, in terms of the Talebian metaphor, black swan events are supposed to be infrequent. But La Merle points out that, for various reasons, we could be looking at a future that features flocks of black swans: