(17)In most cases a buy-in process should be initiated where the financial instruments are not delivered within four business days of the intended settlement date. However, for illiquid financial instruments it is appropriate that the period before initiating the buy-in process should be increased to a maximum of seven business days. The basis for determining when financial instruments are deemed to be illiquid should be established through regulatory technical standards, taking account of the assessments already made in Regulation (EU) No 600/2014. Where such a determination is made the extension of the deadline for initiating the buy-in process should be up to seven business days.