Advertising agency WPP has seen pre tax profits rise by 19.4 per cent to £524m in the first half of 2013, but concerns for the future remain, and WPP's "operating companies remain cautious" (release).
Yet again the firm's management refer to the chance of "grey swan" events. Here are the four they have in mind:
Eurozone crisis, the Middle East, a Chinese or BRICs hard or soft landing and, perhaps, most importantly, dealing with the US deficit, a record $16 trillion of debt and the consequent sequester.
These are events that WPP sees as having a small chance of happening, but will have a large impact if they do.
Grey swans are derived from the concept of "black swans", a term coined by Nassim Nicholas Taleb. Black swan events are typically completely unexpected, and computer models and humans tend not to account for their possibility.
Think earthquakes, personal computers, the Great Depression and terrorist attacks. By contrast Grey swans aren't completely unexpected - but are responsible for a lot of volatility nonetheless.
While firms can try to anticipate them, the associated potential costs and benefits are massive, and difficult to insulate against.
It's not the first time that Sorrell has voiced concerns about grey swan events either. Last year he tried to draw attention to the phenomenon.
Here's Sorrell from last October, when he names the exact same "grey swan" risks: