Deciphering conspiracy theories is all the rage. As the film of Dan Brown's global bestseller The Da Vinci Code opened to critical reviews last week, millions will be left confused and unconvinced by its labyrinthine plot. Like the movie, the announced departure last week of the devoutly Catholic John Studzinski as head of investment banking from HSBC poses more questions than it answers.

The biggest mystery of all is why "the world's local bank" found itself in such a parlous position in advising big companies that it needed to hire Studzinski to build a serious presence in investment banking. With its huge balance sheet, heritage and strong footprint in the UK and Asia through the likes of James Capel and Wardley, bulge bracket status should have been its birthright.