Credit Suisse's biggest backer says can't put up more cash; share down by a fifth
The head of Credit Suisse Group's largest shareholder, Saudi National Bank (SNB) , said on Wednesday it would not buy more shares in the Swiss bank on regulatory grounds.
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### Instruction: Credit Suisse's biggest backer says can't put up more cash; share down by a fifth

### Response: The head of Credit Suisse Group's largest shareholder, Saudi National Bank (SNB) , said on Wednesday it would not buy more shares in the Swiss bank on regulatory grounds.