This Was Not a Broker Cancellation

When something like this happens, clarity is important.

The broker does not cancel such trades.

The cancellation is done automatically at the exchange level under NSE’s surveillance mechanism known as the Reversal Trade Cancellation Mechanism (RTCM).

RTCM was introduced through NSE Circular No. NSE/SURV/65645 dated December 17, 2024.

The official circular can be accessed here: NSE – Reversal Trade Cancellation Mechanism Circular

What RTCM Actually Monitors

NSE tracks intraday trades between pairs of counterparties (identified via PAN or CP codes).

If two parties buy and sell the same contract between themselves in a reversal pattern — especially where quantities and price differences cross certain thresholds — the exchange system may cancel the trade automatically.

The evaluation considers multiple factors together, including:

• Reversal quantity compared to total market volume
• Buy vs sell ratio between the same two entities
• Price impact on square-off
• Concentration of volume between the same counterparties

Only when all conditions are triggered does cancellation occur.

Why Deep OTM Strikes Can Trigger It

The strike in question was significantly out-of-the-money.

Deep OTM index options generally have:

• Lower traded quantity
• Wider spreads
• Fewer active participants

In such situations, even moderate trading between the same counterparties can represent a large portion of total market volume.

That structural reality increases the probability of triggering RTCM.

Does This Imply Manipulation?

Not automatically.

Surveillance mechanisms are designed conservatively to protect market integrity.

Sometimes legitimate trades in illiquid contracts may resemble reversal patterns from an algorithmic perspective.

The key takeaway is not about intent — it is about structure.

The Larger Lesson

At ProStocks, which I run along with my father, we see how market structure continues to evolve.

Trading today is not only about direction or strategy.

It is also about:

• Liquidity awareness
• Execution structure
• Counterparty dynamics

Understanding surveillance frameworks is now part of being a serious derivatives participant.