Would you invest in Manchester United?

With 53m followers on Facebook, a Wall Street valuation of $3.6bn (up from $2.8bn in May) and a 10 year deal with Adidas worth $1.3bn, Forbes puts Manchester United third in the world of most-valuable teams.

Madrid and Barcelona are the only teams to be worth more.

And this despite finishing seventh in the Premier League, the recent departure of David Moyes following the charismatic Sir Alex Ferguson’s retirement and the prospect of becoming lost in the wilderness of mid-ranking Premier League teams!

Yet the money keeps on coming: General Motors has just signed a seven year deal worth $559m with them, so next season Messrs Rooney et al will be sporting the Chevrolet logo on their shirts.

What is going on?

Are these otherwise rational brands caught in the glare of Manu’s past, like rabbits in the headlights, unable to come up with a comparable alternative? Even though there is no reason why Manu shouldn’t disappear from the top ten for years to come.

Is it the lemming instinct? Surely they are committing some sort of commercial suicide, or at best, taking on a huge amount of risk.

Or do they know something we don’t? That commercial success off the field isn’t linked to sporting success on the field. Maybe they think that the brand has so much market traction that it is bigger than the beautiful game.

Maybe they’re right. I’m sure they’ve considered it from every angle, done their scenario planning and reached their conclusions in a rational, justifiable way.

But it looks like a risky investment to me.