As Manchester United fans are discovering, change at the top is not always a good thing.
Doubts currently hover over retailers Sainsbury (LON:SBRY) and Burberry (LON:BRBY), as both are set to lose highly respected chief executives this year.
The good news is that a changing of the guard does not necessarily lead to a share price slump, even when the departing CEO is regarded as a management superstar.
Even after this week’s plunge, the share price of Rolls-Royce (LON:RR) is up by almost two-thirds since highly respected boss Sir John Rose left in March 2011; computer chip designer ARM (LON:ARM) has seen its share price rise 16% since Warren East cashed in his chips last June while electrical components firm Premier Farnell (LON:PFL) has seen its shares climb by a third since Harriet Green jumped ship for travel firm Thomas Cook in June 2012.
Given the experience at Tesco (LON:TSCO) after Sir Terry Leahy left, however, Sainsbury’s shareholders have cause to fret.
There are those who say the redoubtable Leahy quit while he was ahead after a King Canute moment when he realised that he was incapable of holding back the tide for much longer, leaving a rebuilding job to his successor.
Weight is given to this view by the shortness of the interval between his departure and the point at which the wheels started coming off the Tesco juggernaut.
More generous souls accept the explanation that after many years at the top in an arduous job, he simply wanted to move on to pastures new.
That is certainly the line Sainsbury's Justin King is taking, while Burberry’s Angela Ahrendts is returning to her native America to take on a prestige job with iPhone firm Apple.
The question remains: in years to come, will wags be referring to Justin King as “Justin Time” for getting out at the top?
As the discount chains and Waitrose attack the market share of the supermarkets in a pincer movement, King's crowning achievement at Sainsbury's has been to maintain or even grow market share.
The latest figures from market research firm Kantar Worldpanel show Sainsbury's is alone among the big four supermarket chains in growing market share – but only just.
In the four weeks to 2 February, Sainsbury's market share was up 0.1% (gross), with Tesco down by 0.8%, Asda down by 0.7% and Morrisons down by a worrying 4.0%.
As veteran retail analyst Nick Bubb observed: “Take 2% to 3% off all those figures to allow for new store sales growth and the like-for-like figures don’t look great.” So it might well be an opportune time for King to get out.
Bubb reckons “food retailers may be facing a structural change in consumer behaviour”, with big out-of-town hypermarkets falling from favour, while online shopping, click to collect and convenience store top-ups, are now where it is at for food buyers.
King has possibly decided that he does not want to be one of those generals who fights the current war using the tactics of the last, and is making way for someone with fresh ideas.
Fabled investor Warren Buffett once said you should invest in a company so good that any fool could run it, because one day some fool will.
Sainsbury's boss-in-waiting, Mike Coupe, is not regarded as a fool, or the sort who will bet the company in a GEC-style “death or glory” gamble on growth.
Mike Dennis, of broker Cantor Fitzgerald, expects Coupe to “retain a lot of the existing sales strategy”, though Dennis acknowledges it will be tough for Sainsbury’s to continue to out-perform in 2014, “as the improvement in customer loyalty from Brand Match is unlikely to be repeated”.
Dennis thinks the shares are worth holding.
That’s not quite a cry of “the King is dead; long live the Coupe”, but it is an endorsement of the view that new bosses should be given a bit of time to prove their mettle … even Fergie’s successor at Manchester United, David Moyes.