The Reserve Bank of India (RBI) has introduced new rules that restrict how much banks can lend to companies for proprietary trading (trading using the firm's own money instead of clients' money). These rules, which started in July, have already caused a major slowdown in the equity derivatives market (a market where people trade contracts based on stock prices). In just four days of trading, the total value of these trades has dropped significantly, showing that the squeeze on bank funding is working through the system.

Data from the National Stock Exchange (NSE) shows that the average daily turnover (the total value of trades done in a day) fell by 25% in the last four sessions. It dropped from over Rs 1.63 lakh crore last month to about Rs 1.22 lakh crore. The impact was even bigger on the Bombay Stock Exchange (BSE), where volumes fell by 30%. The hardest hit areas were index futures and options, where the money paid for premiums crashed by 45%. This shows that without easy bank credit, trading firms are struggling to maintain their usual activity levels.

Proprietary trading firms are the main players involved here. These firms use large amounts of capital to provide liquidity (the ability to buy or sell easily without changing the price) to the market. Now, they are facing a liquidity impact of more than Rs 50,000 crore because of the new lending curbs. Experts from the Capital Market Participants Association of India warn that if Indian firms cannot trade easily, foreign firms might take over their market share. This could lead to a loss of tax revenue and jobs within the Indian financial sector.

For bank officers, this change means a shift in credit risk and portfolio management. Banks can no longer provide easy funding for speculative (risky) trading activities as they did before. This move by the RBI aims to reduce the risk of bank money being used in volatile stock market bets. However, it also means that the income banks earned from lending to these trading desks might decrease in the short term. The rising cost of funding is forcing traders to be more selective, which means fewer loan requests for margin funding (borrowing money to trade).

Market analysts believe that trading volumes will stay low for some time. When funding costs go up, many traders simply stop trading or reduce their position sizes. This also leads to higher 'impact costs,' which is the loss traders face due to the gap between buying and selling prices (bid-ask spread). While large investors might not feel the pain immediately, high-frequency traders who operate on very thin margins will find it very difficult to survive under these new rules.

Stock prices of market intermediaries have already reacted to this news. Shares of the BSE and MCX fell by 3% recently as investors worry that lower trading volumes will lead to lower fees for the exchanges. Although some experts believe the market will eventually adapt to the new framework, the immediate future looks quiet. Bankers should watch for a shift in how these trading firms restructure their capital, as they move away from bank loans toward using more of their own internal funds.