mumbai, Aug. 20 -- The Securities and Exchange Board of India (SEBI) is pushing ahead with a set of changes meant to smooth out trading on the stock exchanges, with one affecting how orders are placed in the final minutes of each trading day, and the other targeting the rules that govern small and medium enterprise (SME) listings. From September, stockbrokers will be able to accept trade orders during the first few minutes of the closing auction session (CAS), the window at the day's end when the exchange sets the final closing price for a stock, two people in the know told Mint."Starting September, we will begin accepting aftermarket orders between 3:15 and 3:20 pm. The move is expected to improve price discovery and liquidity in CAS," said Dhiraj Relli, managing director and chief executive officer at HDFC Securities. The first 5 minutes of the 20-minute CAS are dedicated to calculating the reference price and transitioning to the auction system. CAS begins at 3:15pm and ends at 3:35pm. The acceptance of after-market orders will help discover prices more accurately as liquidity improves. Separately, the markets regulator is considering a change to the rules for the SME segment-the part of the market where smaller companies raise money and list their shares, typically with lighter compliance requirements than those on the main exchange boards. The review comes as the regulator grapples with a market-making framework that has failed to deliver enough liquidity while adding costs for companies, and with trading rules that can leave investors holding shares they cannot easily sell. "The market-making framework is not working properly. And the cost is increasing due to that market-making. The underwriting system is not working. And it should be given a lot of cost. So it is becoming more costly than the main board," SEBI chair Tuhin Kanta Pandey said at an event on Wednesday. Under the market-making framework, designated intermediaries are required to continuously provide buy and sell quotes for a stock, helping support liquidity and smoother trading. The changes are being considered as part of a thematic review of the SME framework....