For institutions stuffed with ferociously clever people it’s really quite remarkable how spectacularly stupid banks can sometimes be.
Take Morgan Stanley. The bank’s equity team this week issued a warning to its clients that a Labour government could pose every bit as much of a risk to British businesses as Brexit.
For a start that’s debatable, particularly if Mr Corbyn pursues a more constructive relationship with our European partners than the Tories have, as seems likely.
But it also offered Mr Corbyn a wonderful early Christmas present, beautifully wrapped and with one of those little frilly ribbons on top that people seem to like.
So naturally he said thanks very much, and issued a social media post railing against the “speculators and gamblers who crashed our economy in 2008”.
He also noted the absurd multi million dollar salary handed to Morgan Stanley’s boss and the billions banks paid out in bonuses, contrasting them with the situation confronted by Britain’s nurses, teachers, builders, shopworkers and other more humbly remunerated workers who perform functions that are of considerably more value.
On, and let’s not forget the vast settlement Morgan Stanley paid in the US for its role in flogging bonds backed by dodgy mortgages.
In Mr Corbyn’s Morgan Stanley Christmas box was a football, along with a note inviting him attend his local Goals Soccer Centre to see how many times he could shoot it into an open goal. The answer to that is an awful lot.
The coup de grace? Mr Corbyn declared Labour to be for the many by contrast to the banks, and by implication, their friends in the Conservative Party.
The only goal scored by Morgan Stanley in this match was an own goal.
Ultimately, however, such sniping, while highly entertaining and a delight for people like me, is in the interests of neither party.
Like it or not, the banks look like they are going to have to work with Mr Corbyn who is a solid favourite to become the next Prime Minister (I’d describe the 5-1 best price offered by Paddy Power as a prudent investment).
But Mr Corbyn is also going to have to work with the banks, particularly if he wants to give his radical programme every chance of success.
Both sides need to find a way to talk to each other that doesn’t involve megaphones and social media spats.
I was recently told by a very senior banker that a notable absentee from the City cocktail circuit is John McDonnell, Mr Corbyn’s shadow chancellor.
Business picture of the day
In one respect I can understand that. I’ve been to many of those events myself and they can be insufferable. But in another, it’s something Mr McDonnell is getting wrong.
Lines of communication need to be opened. It would be helpful for the country, not just Labour, for alliances to be formed with, if not like minded people, then at least those who aren’t as opposed to his project as Morgan Stanley’s scribblers appear to be.
It might surprise him to learn that they do exist. Surely a few glasses of fizz and some of those silly canapes they distribute at these events would be a small price to pay for finding that out. No one would dare suggest it would make a champagne socialist of Mr McDonnell.