Shares of Bharat Heavy Electricals, Gujarat Narmada Valley Fertilizers and Chemicals, Manappuram Finance and Canara Bank are under futures and options (F&O) ban for trading on Wednesday. However, the stocks will be available for trading in the cash market. The F&O ban is in place when the open interest crosses 95% of the market-wide position limits. The ban lifts when the open interest falls below 80%. Meanwhile, the Karnataka assembly election, Q4 earnings and US inflation data are being closely monitored by investors.