Securities and Exchange Board of India (Sebi) has issued show-cause notices to all entities allegedly involved in the IPO-demat scam asking them why further inquiry cannot be initiated against them.Sebi has said that all those named in the scam have violated its regulations. All those served the notices have been given 10 days to reply, and some of them have already replied denying such violations.Sebi had issued an disgorgement order in the second half of November asking depositories and DPs to deposit ill-gotten money totalling Rs 116 crore within six months. It is certain that all named in the order are challenging it before the Securities and Appellate Tribunal (SAT). National Securities Depository (NSDL) has already filed an appeal before SAT saying that Sebi has no power to order disgorgement . A spokesperson of Central Depository Services (CDSL) also confirmed that they will be filing an appeal soon.