The Securities Appellate Tribunal (SAT) has fixed March 31 as the deadline for the Securities and Exchange Board of India (Sebi) to complete its enquiry into Karvy Stock Broking's involvement in the multicrore initial public offering (IPO) scam.SAT asked the market regulator to pass final order in this regard by May this year.Sebi prohibited Karvy last year in May from opening fresh demat accounts as a depository participant pending enquiry into the IPO scam.Dismissing an appeal by Karvy against the Sebi order, SAT said: "The Sebi enquiry officer has been asked to complete the enquiry expeditiously but not later than March 31." "The board will then take a final decision there on in accordance with the law within two months thereafter," the SAT order had said last week.During its investigations in the IPO scam, Sebi had found that Karvy's sub-brokers Roopalben Panchal, Sugandh, Purshottam Budhwani and Manojdev Seksaria cornered lakhs of IPO shares reserved for retail investors.