The domestic equity benchmark indices Sensex and Nifty started on a mixed note in the morning trade on Tuesday following introduction of a new auction mechanism for shares having futures and options (F&O) contracts.

The Closing Auction Session (CAS) in the equity cash segment became operational on Monday, introducing a new auction-based mechanism for determining the closing prices of eligible stocks in a move aimed at making the price discovery process more transparent and robust, according to news agency PTI.