Periodic Call Auction rationalization narrows illiquidity criteria, mandates minimum auction sessions and allows order carryover. Rationalization tightens the Periodic Call Auction framework by defining illiquid scrips through a low average turnover measure applicable across all trading exchanges and prescribing exclusions based on market capitalization, dividend history, and a combined profitability, pledged promoter holding and book value test. Exchanges must keep a scrip in the auction for at least one quarter, provide at least two daily auction sessions with a uniform closing session, allow orders to remain valid all day and carry un matched orders into the next session, and implement systems and bye law amendments from the next quarter.