Warburg's shares fell 12p to 736p yesterday following the departures of Maurice Thompson and Michael Cohrs to rival Morgan Grenfell, which, under its owner Deutsche Bank, is set on expansion in London. The shares were down 22p at one point before partially recovering.
Mr Hobley has spent the past five years leading Warburg's corporate finance effort on the Continent. His former co-head, Mark Nichols will take sole charge for the time being.
Since the collapse of merger talks with Morgan Stanley in December, Warburg is seen to be in an increasingly precarious positon. In recent weeks, it has been rumoured to be the takeover target of another US or European investment bank.
In contrast, Morgan Grenfell has been charged with leading Deutsche Bank's expansion of its investment banking in London and worldwide.
SG Strauss Turnbull said it cut the profit forecasts for SG Warburg and added that Kleinwort Benson was a more attractive investment in the sector.