Credit Suisse tried to assuage fears about its health in a memo to employees and in a round of phone calls to investors and clients over the weekend, according to people familiar with the matter.

Credit Suisse shares are down 21% over the last month and spreads on its credit default swaps, a type of insurance against default, rose to their highest level of the year on 30 September. The deteriorated market condition indicates that Credit Suisse could struggle to raise new shares to pay for a planned restructuring and that its funding costs could rise sharply.