$Credit Suisse Group AG(CS)$ shares slid on Wednesday, dropping by as much as 10.5% to a new record low, as its largest investor said it could not provide the Swiss bank with more financial assistance."We cannot because we would go above 10%. It’s a regulatory issue," said Saudi National Bank(1180.SE)chairman Ammar Al Khudairy saidon Wednesday.The Saudi lender acquired a stake of almost 10% last year after it took part in Credit Suisse's capital raising and committed to investing up to 1.5 billion Swiss francs ($1.5 billion).Credit Suisse on Tuesday published its annual report for 2022 saying the bank had identified "material weaknesses" in controls over financial reporting and not yet stemmed customer outflows.Switzerland's second-b