If you're just coming back from your holidays, you may find your list of contacts needs some updating.

In the past week alone, top executives from three of the world's largest companies have exited. That caps a series of exits this year, and follows a huge year of goodbyes in 2018.

The reasons behind the departures have been varied, but the implications are all the same: they've left big holes to fill.

So far, the replacements have been, frankly, uninspired.