The defection of 48 UK and Irish clients in six months underlines the questions facing AllianceBernstein, a US asset manager whose portfolios came unstuck last year. One of them goes straight to the heart of the future of active asset management.

The losses account for £3bn, only a small part of AllianceBernstein's global assets under management, which amounted to $500bn at the end of September. But it is about a sixth of its UK and Irish client base, and other clients, such as Suffolk County Council Pension Fund, are watching how the situation develops.