According to the CISI UAE Financial Rules and Regulations under Client Protection provisions, when a client buys and sells securities within the same trading session (day trading), the client must maintain sufficient credit to cover the value of purchase in their cash account at the time of the transaction. This rule ensures that clients have the necessary funds to settle their purchase obligations promptly, reducing settlement risk and maintaining market stability. Credit to cover sales is not required since sales generate funds rather than consume them. This provision supports orderly trading and financial discipline among market participants by preventing unsettled trades and possible defaults.