From the conversation
“Two unrelated participants exerting opposite pressure on the same expiry auction is a market-structure question, not a single-actor one.”
On why settlement days are different
On an ordinary session, a stock print in the closing auction mostly settles the cash close. On a derivatives settlement day the same print can change the value of a much larger futures and options book. That is the structural link: an order in the cash auction can have its economic payoff in derivatives.
On two books, opposite directions
SEBI's first CAS order named Copthall Mauritius and Mansi Share and Stock Broking. The point from the desk was not to retell a two-firm story. The order itself shows different signatures in the same auction — buy-side concentration on one side, a large sell block cancelled within seconds on the other — rather than a single coordinated actor.
On the cash print versus the options book
A few crore in the cash auction is not the story on its own. Speed and forward risk are. Cash-market orders in a 20-minute window can move the Indicative Equilibrium Price while the economic payoff sits in a much larger options book. Higher CAS turnover on settlement days is not, by itself, evidence of manipulation. The question is whether those cash orders have a clear link to derivatives positions.
On what implied volatility can show
A sharp dislocation in front-expiry implied volatility against a relatively stable next-week series can mean risk is concentrated in the settlement event, not in forward volatility. IV behaviour alone does not establish manipulation. It is a signal to read cash-market activity, IEP moves and derivatives positioning together.
The excerpts above are from Shai Coelho's remarks as published by NDTV Profit. The interview segment is on YouTube; the written piece is at NDTV Profit. Market commentary is educational and observational; it is not investment advice or a trading recommendation.