DUBAI, UNITED ARAB EMIRATES -- The chairman of Saudi National Bank resigned for "personal reasons" after his comments on Credit Suisse sent that firm's stock cratering, a regulatory filing in the kingdom said Monday.

The filing on Riyadh's Tadawul stock exchange announced Ammar al-Khudairy's resignation from Saudi National Bank. It dated his resignation as coming on Sunday.

Shares of Credit Suisse sank over 30% after al-Khudairy announced March 15 that its biggest shareholder -- the Saudi National Bank -- would not provide more money to the Swiss lender. Hours later, Switzerland's central bank agreed to lend Credit Suisse up to 50 billion francs (US$54 billion) to shore up its finances.

Swiss authorities later cut a deal with its bigger rival UBS to acquire troubled Credit Suisse at a marked-down price.