Arturo de Frias, of Evolution Securities, said the likes of Credit Suisse and Deutsche Bank had reported Q4 investment banking revenues 20 per cent below the average quarter in 2010 "and we have a similar forecast for Barcap. If every other investment bank is down why would they be up?"
Better conditions for Barcap in the first six months of 2010, and significantly lower bad debt provisions for the wider group, particularly in its high street arm, are expected by the City to have driven annual profits up 24 per cent to a consensus 5.68 billion.
Group annual revenues are estimated to have been flat at 30.3bn.
Diamond, who will present the results on Tuesday, is expected to highlight his thoughts on Barclays' strategy with him at the helm.
He has previously indicated that he sees strategy being "more evolutionary than revolutionary" following on from predecessor John Varley, while there will also be details on Barclays' bonus pool.
American-born Diamond and Varley waived bonuses for 2008 and 2009, although as head of Barcap the new chief executive made multi-million pounds packages in previous years. He has not said what he will do with regard to 2010.
Diamond triggered protests after a recent Treasury Select Committee appearance when he said the time for remorse by bankers was over, and it was now better to focus on the part banks could play in promoting economic growth.