(Adds details)

June 13 (Reuters) - Commerzbank lowered its 2008 outlook for Deutsche Bank AG (DBKGn.DE: Quote, Profile, Research), Credit Suisse AG (CSGN.VX: Quote, Profile, Research) and UBS AG (UBSN.VX: Quote, Profile, Research), saying it expects the European investment banks to post additional losses related to their structured and leveraged finance portfolios.

The brokerage, which cut its price targets on all three investment banks, downgraded Deutsche Bank to "add" from "buy," saying it sees some "acquisition risk" for the bank due to consolidation in the German banking sector.

Commerzbank, however, upgraded UBS to "hold" from "sell," and said the bank's recent rights issue may improve management's plan to lower risk-weighted assets, but that this will lead to lower underlying revenues for Switzerland's biggest bank.

"Exposure to structured finance and monoliners is high (for UBS) and negative news flow in wealth management is likely to continue," the brokerage said, adding that despite its upgrade of the stock, UBS remained its least preferred European investment bank.

The brokerage rates Credit Suisse "hold." Credit Suisse continues to gain from UBS' weakness in Swiss wealth management and also has considerably lower exposure to structured finance products than its Swiss rival, the brokerage said.

OUTLOOK CUT

Additional losses related to banks' exposures to structured and leveraged finance portfolios is expected to be about 1.3 billion euros at Deutsche Bank, about 1 billion Swiss francs at Credit Suisse and about 2.5 billion Swiss francs at UBS, the brokerage said.

However, losses were materially below that reported by the investment banks in their first quarter, the brokerage said.