A Credit Suisse analyst on Thursday cut his rating on UBS AG, less than a month after the Swiss investment bank moved to raise $15.5 billion to shore up its balance sheet.
Analyst Daniel Davies downgraded UBS to "Neutral" from "Outperform."
Last month the company sold shares at a 31 percent discount in the offering, and $15 billion in subprime and alt-A mortgage assets to BlackRock Inc.
"Now that the write-downs have been reduced to manageable levels ... management face the challenge of rebuilding the franchise," Davies said in a note to clients. "We expect this to be a difficult job."
Shares of the company trading on U.S. exchanges have slipped 45 percent so far this year.