Guide · Market structure · Updated 2026-09-23

When delivery fails, the buyer is made whole and the seller pays a price set by formula

Most retail traders meet this mechanism once, by accident, and learn it from a debit they did not expect. The usual cause is mundane: shares sold before they were credited, or a holding that was pledged and not released in time. Nothing dishonest happens, and yet the settlement system treats it exactly as it treats any other failure to deliver, because from the clearing corporation's side the two are indistinguishable.

Understanding what happens next is worth more than the fright. It explains why Indian settlement is as reliable as it is, and it shows precisely where the risk was moved to.

The buyer's leg was never the question

A settlement system earns trust by making one promise: if you bought and paid, you receive. Honouring that promise when a counterparty fails requires somebody to stand in the middle, and that is what a clearing corporation does. It becomes the counterparty to both sides, so the buyer is not exposed to the seller at all.

This is why a buyer meets a short delivery on their own purchase only as a delay. The shares arrive a settlement day late, through the auction, or the money arrives instead at the close-out price, and the failure is resolved behind the interface. The only party who pays for it is the one who caused it.

The auction, and who is not in the room

To deliver shares it does not have, the clearing corporation has to buy them. It does that through a separate auction session in which other participants offer the security. The shares sourced there go to the buyer, and the cost is charged back to the seller who failed.

The seller is not a participant in that auction. They do not bid, they do not set a reserve, and they cannot withdraw. The price is discovered among other people entirely, and the defaulting seller receives the result as a charge.

That asymmetry is the whole design. A guarantee has to put its risk somewhere, and here all of it is placed on the participant who broke the obligation. Nothing about it is arbitrary, but it does mean the seller's downside is not knowable at the moment the problem arises.

The close-out, and why the premium exists

Sometimes the auction cannot source the shares, because the security is illiquid, or because nobody is willing to sell into that session. The obligation still has to be extinguished, so a close-out applies: the matter is settled in cash at a price determined by formula against defined reference prices, with a premium applied above them.

The premium is the part that looks punitive and is actually structural. Consider what a close-out at the plain market price would create. A seller watching a position move against them could simply decline to deliver, accept a cash settlement at market, and have converted a delivery obligation into a costless exit. The premium removes that. It makes delivering the cheaper path in every case, which is the only way to keep non-delivery genuinely exceptional rather than a tactic.

The debit that arrives before the auction does

There is a step between the failure and the auction that surprises people, because it happens while the outcome is still unknown. Once a shortfall is identified, the seller's obligation is live and the money at risk has to be secured. Rather than waiting for the auction to settle and then presenting a bill, the clearing member withholds the sale proceeds and holds margin against the position, because the eventual charge is not yet known and could exceed what the sale brought in.

So the sequence a seller actually experiences is: the sale proceeds do not arrive, an amount is held, and only afterwards does a final debit or a partial release follow once the auction or close-out has settled. Reading the first of those as the penalty and the second as a second penalty is a common misreading. There is one charge. What came before it was a hold against an unknown.

This is also why the exposure cannot be bounded by looking at the screen. The seller's obligation is to deliver a quantity of a security, not to pay a sum of money. Converting that obligation into a sum is exactly what the auction does, and until it has run, the number does not exist.

The shortfall the netting hides, and the auction that now finds it

A broker's trades reach the clearing corporation as a net position, and netting can swallow a failure. If one client is short a security on a given day and another client of the same broker is due to receive that same security, the broker's net position may show no shortfall at all. One client did not deliver and another was entitled to receive, and the broker's single number hides both. That is an internal shortage, and the rules for it changed in 2025.

Until March 2025 such a shortfall could stay inside the broker's books, because the clearing corporation's auction saw an internal shortage only if the broker reported it. Before direct pay-out the broker did not have to. Bought shares were paid out to its pool account and passed on by the broker, which settled an internal shortfall between the two clients at a rate its own policy set, charging the client who failed and compensating the one who did not receive, and that rate differed from broker to broker.

Two changes ended that. SEBI's circular of 5 June 2024 on direct pay-out of securities (SEBI/HO/MIRSD/MIRSD-PoD1/P/CIR/2024/75) required internal shortages to be handled through the auction the clearing corporation specifies, and NSE Clearing's operating guidelines made reporting them for auction compulsory once direct pay-out began (NCL/CMPT/63669). Direct pay-out, which started on 25 February 2025, also needed every selling client's shares to arrive through the pay-in, because the clearing corporation now credits bought shares straight into each client's own demat account rather than the broker's pool. From 7 March 2025 NSE Clearing stopped depending on the broker's report and identifies internal shortages itself, at every broker except the custodians that clear for institutions (NCL/CMPT/66688 of 14 February 2025). It adds up what each of the broker's selling clients owes in a security, compares that gross sell obligation with what the broker actually paid in, and treats any shares a broker hands to its own buying clients outside the pay-in as not received.

What follows is set by the clearing corporation's rules, not the broker's (NCL/CMPT/73996 of 30 April 2026, items 6.3, 6.4 and 7.13). The broker must pay a valuation amount, priced at the settlement price plus 20 per cent, into its settlement account by noon on the settlement day; if it does not, no auction is held. The shortfall then enters the same auction as every other failed delivery that afternoon, and shares bought there go to the receiving client through the auction's own settlement. Where the auction finds no seller, NSE Clearing has closed the shortfall out itself since 14 November 2025, debiting the broker at the auction rate and crediting it at the close-out price, and the broker passes the debit to the client who failed and the credit to the client who did not receive (NCL/CMPT/71045, and the FAQ in NCL/CMPT/71441). Where no auction was held at all, the broker must still pass close-out entries at the clearing corporation's auction rate or, failing that, its close-out rate.

What still differs from a shortfall at the clearing corporation is written into the same consolidated circular. The auction of an internal shortage waits on the broker's valuation, the clearing corporation describes it as only a facility carrying no settlement guarantee, and it charges a facilitation fee of 1 per cent of the value of the securities, at the price of the day before the auction, collected monthly; whether a broker passes that fee on is a term of its own tariff. For the seller the consequence is plainer than it used to be: an internal shortfall now ends at an auction outcome or at the close-out formula, like any other failure, rather than at a rate that differed between brokers. The hour-by-hour timeline, and how many lines the auction list carries each day, are in the guide to what T+1 settlement does to a trade.

Where there is no auction to run

An auction needs somebody willing to sell into it. Some securities are placed in segments and surveillance frameworks that constrain how they may be traded, including settings where every trade must be settled by delivery and intraday netting is not available. In those conditions the pool of participants able to offer the security into an auction session is thin, and in certain series the auction route is not the applicable mechanism at all.

What follows is a direct close-out at the formula price. That removes the one favourable possibility a defaulting seller might have hoped for, which is an auction that settles near the market. It is worth noting which of your holdings sit in restricted frameworks, because the same operational slip carries a different worst case depending on what was sold.

The same architecture on the other side

Delivery is only one of the two legs. A buyer who does not fund their purchase is also a settlement failure, and it is handled by the same principle rather than by a different one: the counterparty is protected, and the failing participant absorbs the consequence. The seller is paid regardless, because the buyer's broker must meet its obligation to the clearing corporation at the pay-in whether or not its client has paid, and a broker that falls short loses its trading facility and has its securities pay-out withheld once the shortfall reaches 5 lakh rupees. The purchase itself is not cancelled. Under direct pay-out the clearing corporation still credits the shares to the buyer's demat account, pledged to the broker's Client Unpaid Securities Pledgee Account when the broker reports the client unpaid, and by existing practice the broker may invoke that pledge and sell the shares only within five trading days of the pay-out (NSE/INSP/75508, guideline 8.3).

From 31 October 2026 that practice becomes written rule, under SEBI's circular of 3 July 2026 and NSE's operational guidelines of 31 July 2026. Unpaid status is judged on the end-of-day clear ledger balance, the client must be told what was pledged before the next day's trading, and the broker's written policy sets how long the client has to pay, at most those five trading days. After reasonable notice the broker sells the shares under the client's own client code; it may give no trading exposure against them; and a pledge neither invoked nor released within five trading days is released by the depository at the end of the sixth. From 3 January 2027 a broker may also extend a pledge, a week at a time, for a narrow list of reasons such as a stock stuck in its lower circuit. The day-by-day sequence for a trader who buys one day and sells the next is worked in the guide to what T+1 settlement does to a trade. The same exposure is why margin is collected before the order rather than after it.

Seeing both sides at once makes the design legible. The clearing corporation is not adjudicating who was at fault or why. It has two obligations to discharge, it discharges them, in shares or in cash, and it recovers what that cost from whoever did not perform. Intent never enters the calculation, which is precisely why an honest operational slip is treated exactly like anything else.

How an ordinary retail seller gets here

None of the common routes involve selling something never owned. They involve selling something owned but not yet available.

The compression of the settlement cycle matters here. A shorter cycle leaves less time between placing a sale and having to deliver against it, so a habit built when the window was longer now has less slack in it. The discipline that survives the change is simple: sell what is credited and unencumbered, and treat everything else as not yet available.

What this says about the system, and about you

Both are true at once, and holding both is the useful position. The reason you can buy shares in an Indian listed company without investigating who is on the other side is precisely that somebody has agreed to absorb this failure and charge it onward. The cost of that convenience is that when you are the one who fails, you meet a price you did not negotiate.

It also puts a specific discipline in front of anyone trading actively: what is deliverable right now is a different question from what the portfolio says you own, and it is a question worth being able to answer before a sell order, not after a debit.

The wider lesson generalises past this one mechanism. A retail participant sees a price, a quantity and a button, and it is easy to conclude that the price is the whole of the transaction. It is not. Behind the button sits a settlement obligation with its own deadline, its own guarantor and its own remedy, and that obligation is what you actually entered into. Most of the time it discharges invisibly and the abstraction holds. The value of understanding this particular failure is not that it is likely, because for a careful seller it is not, but that it is the clearest available view of what was underneath the abstraction the whole time.