For anyone worried hedge funds could spark another market crisis, Wednesday is a red letter day: the final chance for investors to put in demands for their money back by the end of September at many funds using standard redemption terms needing 45 days’ notice.

By Thursday, hedge funds with these terms will know exactly how much cash they must find to repay shareholders; cash they are likely to find by selling their investments. Large-scale redemptions may prompt big sell-offs; something BNP Paribas analysts say could cause “irrational” markets.