Mumbai, Oct. 14 -- Revenue growth at stock brokerages is likely to slow sequentially in the July-September quarter as lower derivatives and cash-market trading volumes weigh on their core broking businesses, analysts said.The average daily premium turnover (ADPT) in index options on the National Stock Exchange of India (NSE) fell 27% sequentially in the September quarter, according to exchange data. Average daily turnover in the cash segment declined 19% over the same period.The Securities and Exchange Board of India (Sebi) reset the framework for the closing auction session (CAS), affecting futures and options (F&O) activity, while weak market sentiment weighed on cash-market volumes, Motilal Oswal Financial Services (MOSF) said in its p...