Deutsche Bank AG warned of weakness to come in its core investment banking division, laying bare the challenge facing its two new CEOs named only hours earlier.

The bank warned it may miss its goal of generating 6.4 billion euros pretax profit ($9.2 billion) from investment banking due to the European debt crisis.

The target is now dependent on swift and sustained resolution of the European sovereign debt crisis and a return to a significantly improved operating environment in the second half of 2011, said Germany's flagship bank, although it reaffirmed its aim to deliver 10 billion euros for the group as a whole, with other divisions taking up the slack.

That leaves the global investment banking heavyweight more dependent on retail banking and wealth and asset management to meet the full-year targets set by outgoing Chief Executive Josef Ackermann, and analysts remain sceptical.

Nobody really believed that Deutsche would reach its 10 billion euros goal, Philipp Haessler, an analyst at Frankfurt-based Equinet, said.

A Reuters poll compiled before Deutsche Bank published its results showed that banks and brokerages on average expect the lender to post 2011 pretax profit of about 8.7 billion euros.

Poor trading has also dampened results at rival Goldman Sachs and forced Switzerland's UBS to slash costs and scrap earnings targets set in 2009.

Deutsche Bank shares were down 0.4 percent at 38.06 euros at 1120 GMT (7:20 a.m. EDT), slightly outperforming the STOXX Europe 600 Banks index <.SX7P>, which was 0.6 percent lower.

ACKERMANN'S SHADOW

Deutsche Bank's earnings figures came hours after it named investment banking head Anshu Jain and Juergen Fitschen, head of its business in Germany, as co-chief executives from 2012.

It also said Ackermann would replace supervisory board chairman Clemens Boersig, putting him in a position to influence the bank's strategy and appointments to its board.

Fears that Deutsche Bank could neglect its German roots and expand risk-taking activities prompted key members of the supervisory board to opt for the dual CEO model, adding Fitschen's contact book in Germany to Jain's ability to deliver profits.

But some industry observers said Deutsche Bank's decision to keep Ackermann on as chairman, also announced late on Monday, would put a leash on Jain.

We are concerned that Ackermann moving from CEO to Chairman would maintain the status quo in strategy - meaning business as usual on an operational basis with Anshu Jain constrained in making his mark on the group, analysts at J.P. Morgan said.

The desire to crimp Jain's influence at the 141-year-old lender reflects widespread suspicion of investment banking, and offers a glimpse into tensions that have dogged Deutsche Bank for the best part of 20 years.

Jain -- who is in charge of some of the world's most risk-hungry traders -- has struggled to build a network in Germany, since this was traditionally the stomping ground of either Fitschen or Ackermann.

Deutsche Bank's chief executive has traditionally played a key diplomatic and political role in addition to banking duties.

Former German Chancellor Helmut Schmidt used to send the lender's CEO -- rather than his own finance minister -- to represent Germany's interests at international conferences such as G6 meetings.

Despite frequent clashes with Berlin, Ackermann too has managed to establish himself as an accomplished international negotiator given his academic background and his role as chairman of bank lobby group Institute for International Finance.

Ackermann also played a key role in rallying private sector support for a rescue deal for Greece.

Deutsche Bank's second-quarter pretax profit rose 17 percent to 1.8 billion euros, falling short of the 1.97 billion consensus in a Reuters poll. Net profit remained flat at 1.2 billion euros.

It took a 155 million-euro impairment on Greek government bonds in the quarter.

Last week, Morgan Stanley surprised Wall Street with better-than-expected earnings, driven by strong trading in equity and fixed-income markets.

(Editing by Andrew Callus and Sophie Walker)