Sian Miller, CIO, ABN Amro Investments

ABN Amro was recently acquired by RBoS and Santander Totta and Sian Miller says staff are suffering from uncertainty.

"We've grown by the acquisition of many businesses. The problem is, many people, even now, will describe themselves as A or Bs, rather than ABN Amro.

The key thing is any merger or acquisition will have a deep impact on the people. There are divisions of culture and senior people need to see the impacts not just for themselves and how their lives will pan out but the same impacts on their teams.

In some ways, nothing changes immediately but at the same time, everything changes. Worlds are turned upside down.

At the moment there's usually somebody at my door saying how vulnerable they feel and asking me what do I think will happen next."

Ben Wishart, group CIO, Whitbread Group

Ben Wishart, group CIO of Whitbread Group is another M&A veteran having seen Whitbread first acquire lots of hotels and then dispose of other leisure businesses.

"Heavy, deep integration. Always. We have that working model and it's relatively simple.

Similarly, we've done lots of disposals and they're relatively easy. In some ways, any problems there are really those of the acquirer.

Interestingly, where we are finding new complexities is in building a series of joint ventures around the world.

In a business era characterized by far more, not fewer external relationships, joint ventures are neither an acquisition nor disposal.

That makes these relationships a different challenge entirely."

Nick Masterson Jones, CIO, VocaLink

Nick Masterton Jones, currently overseeing a merger at VocaLink, is similarly clear that the focus is people and culture.

"For me the culture clash isn't so exotic as multinational cultures but simply Yorkshire versus home counties. We've now gone for heavy cultural integration to create one company culture and I'm not ashamed to say I'm struggling. It's extremely difficult and sharing experiences with others who've been through it is invaluable. Both companies have long-serving employees and they are very good at what they do. How to change cultures without losing really good people is tough."