Mumbai, Oct. 28 -- The Securities and Exchange Board of India's (Sebi's) decision to revise its closing auction session (CAS) framework has raised hopes of a recovery in derivatives trading and brokerage revenues, offering relief to brokers suffering from a sharp slowdown in key income streams. "The pre-CAS levels on volumes and revenue seen in Q1 FY27 will be a good indicator of where we are headed once the circular comes into action. However, one may not be able to replicate revenues from earlier since broader market factors also have an effect," a broking official told Mint on the condition of anonymity. Introduced on August 3, CAS determined closing prices for 213 F&O-traded stocks through an auction that established a single equilibrium closing price, replacing the final volume-weighted average price (VWAP). However, the framework caused abrupt price swings and uncertainty over settlement values on expiry days, prompting market participants to flag concerns about liquidity and price discovery. In response, Sebi changed course on October 15, restoring the 30-minute VWAP for settling derivatives contracts on expiry days. The changes will take effect on December 7. The auction mechanism had quickly lost favour among traders. From August 3 to September 30, volumes in the closing auction session fell 84% to 4.2 million contracts, while traded value fell 77% to Rs.297.72 crore, according to NSE data. However, trading activity began recovering after Sebi issued a consultation paper on September 12 proposing to roll back the framework-offering an early hint of how market volumes might bounce back once the revised rules take effect on December 7. Between August 3 and September 11, volumes in Bank Nifty futures fell 7% to 22,691 contracts, while total traded value declined 9% to Rs.3,845.53 crore, according to exchange data. By the end of September, however, volumes had recovered to 26,622 contracts, up 9.6%, while traded value rose by 4% to Rs.4,408.12 crore. Nifty futures, however, told a different story. Volumes grew 12% to 62,288 contracts in the initial period through 11 September, before momentum accelerated after the consultation paper to post a 20% gain by month-end at 66,539 contracts. Traded value expanded similarly, stepping up from a 6.4% gain before the consultation paper to an 11% increase by the end of September. At Angel One, one of India's largest brokers, broking revenue accounted for 55% of consolidated gross revenue in the September quarter of FY27, down from 60% both a year earlier and in the preceding June quarter. Groww experienced a similar trend. Broking operations, comprising equity derivatives, cash stocks, and commodity derivatives, contributed 68.4% of total revenue of Rs.1,541 crore in the September quarter of FY27, down from 72.9% in the June quarter and 74.9% in the September quarter of FY26. However, brokers are optimistic about a swift recovery. Two broking officials, speaking on condition of anonymity, said Sebi's latest circular could help brokerage revenues bounce back to levels seen in the first quarter of FY27, before the original CAS framework disrupted trading activity. "Our expectation is that it (volumes) will go back to normal in some ways. We think that from the day it becomes applicable, the normalization will be much faster. So, we don't expect it (volume) will go up. The way we are expecting is it will normalize the problem that it created," Ishan Bansal, co-founder of Groww, said during the company's earnings call for the September quarter of FY27, which took place before Sebi issued its latest circular in October. Angel One is also optimistic about the regulatory changes. "The road ahead is also getting clearer with the Sebi circular yesterday evening on updates to the closing auction session. This will bring greater clarity to traders, and we expect that to create some tailwind for us," Ambarish Kenghe, group chief executive officer at Angel One, said during the company's earnings call for the latest quarter. Amit Majumdar, group chief strategy officer at Angel One, said, "The initial pickup in derivatives activity following the announcement is encouraging, and we expect the improvement in market participation to gather momentum over the coming months."...