"While markets are relieved that the Swiss central bank stepped in, sentiment is bound to remain very fragile, particularly as investors will likely worry about the eventual economic impact of aggressive monetary policy tightening by the European Central Bank (ECB)," she added.
DBRS Morningstar on Thursday became the first global rating agency to cut the bank's credit score, with a downgrade to "BBB", which still qualifies Credit Suisse as investment grade.
Credit Suisse shares are down about 22% this week and poised for their biggest week drop since March 2020 when the COVID-19 crisis wreaked turmoil across world markets.
U.S. shareholders of Credit Suisse sued the bank on Thursday, claiming it defrauded them by concealing problems with its finances.
Credit Suisse declined to comment on the lawsuit.