Citigroup has turned to Hewlett-Packard, the information technology group, for advice on how to revive its fortunes without breaking up the company – a novel move that underlines Citi’s efforts to defend its controversial business model.

People close to the situation said Citi’s top executives had recent talks with their counterparts at HP to learn how, over the past three years, the IT group managed to overcome a crisis similar to Citi’s.