To tackle instances of erroneous trading activities in the securities market, Securities and Exchange Board of India – Sebi on Wednesday proposed a slew of measures for the stock exchanges including well-defined parameters and time-bound approach for deciding on annulment of such trades.The latest suggestions from Sebi comes against the backdrop of at least four instances of faulty trades disrupting the market in recent times, the latest being placing of erroneous orders on the National Stock Exchange in February this year.Releasing a discussion paper on policy with regard to erroneous trades, Sebi said the objective is to "have a uniform policy for trade annulment." Market regulator Sebi has also notified new norms for listing of start-ups and small and medium enterprises on stock exchanges without having to make initial public offer (IPO).Sebi has made amendments of rules to permit listing of start-ups and SMEs in Institutional Trading platform (ITP) without having to make an IPO.In a circular dated October 8, Sebi said that the minimum amount for trading or investment on the ITP would be Rs 10 lakh. The move is aimed at providing easier exit options for entities such as Angel Investors, Venture Capital Funds and Private Equities.