Credit Suisse has asked Swiss regulator Finma for a similar move, according to the report, citing two people familiar with the matter.
The SNB declined to comment in response to a question from Reuters.
Credit Suisse was on the verge of losing a quarter of its value on Wednesday after its largest shareholder said it could provide no further support, prompting the Swiss bank’s chief executive to give further assurances about its financial strength.
Saudi National Bank, which owns 9.88% of Credit Suisse, said it would not buy any more shares in the Swiss bank for regulatory reasons.
“We cannot because we would exceed 10%. It is a regulatory issue,” SNB Chairman Ammar Al Khudairy told Reuters.