The head of US-based investor Pimco Mohamed El-Erian says Britain economically would be less well off if it left Europe.
He told Stephen Sackur on HARDtalk that investors would "start putting in an uncertainty premium" due to the possibility of an EU exit.
You can watch the full interview on the BBC News Channel on Thursday 24 January at 04:30 GMT and Friday 25 January at 00:30 GMT and on BBC World News on Thursday 24 January at 04:30, 09:30, 14:30 and 21:30 GMT.
online (UK only) or subscribe to our
Find out who is coming up on the programme by following us on