SLBM, Explained Simply: The Share-Rental Market SEBI Wants to Fix — and Why F&O Traders Should Care

SEBI's chairman said on August 17, 2026 that a consultation paper on SLBM is coming soon. If you saw the headline and moved on because it sounded like back-office plumbing, this one is worth two minutes — because it touches something very concrete: what happens when your stock option goes into expiry and you have to hand over actual shares.

Let's start from zero. No jargon.

What is SLB?

SLB is renting out shares.

That's the whole idea. If you own shares sitting quietly in your demat account, you can lend them to someone else for a while and charge a fee. They give the shares back later. You keep the fee.

That's it. Think of it like renting out a spare room. You still own the house. Someone pays you to use it for a bit. Then you get it back.

The full name is Securities Lending and Borrowing, and the system that runs it is the Securities Lending and Borrowing Mechanism — SLBM. It has existed in India since 2008.

Two useful details:

• It runs through the exchange, not privately. You don't find your own counterparty.
• The clearing corporation guarantees it. So the lender isn't trusting a stranger to return the shares — the exchange's clearing house stands in the middle. If you lend, you get your shares back.

You can lend for a period up to 12 months, and you set the fee you're willing to accept.

Who borrows shares, and why?

Two main reasons, and the second is the one that matters here.

Reason 1: someone wants to sell a share they don't own. They borrow it, sell it, and buy it back later to return it. That's short selling.

Reason 2 — the one for F&O traders: someone has to deliver shares and doesn't have them.

This is where SLB stops being abstract.

The part that affects your F&O positions

Here's a rule that catches people out.

Since the October 2019 expiry, all stock F&O contracts in India are physically settled. Not cash-settled. Physically. Actual shares change hands.

(Index contracts — Nifty, Bank Nifty — are still cash-settled. This is only about options and futures on individual stocks.)

So at expiry, depending on your position, you either receive shares or you give shares:

Your position at expiry	What happens
Long futures, long ITM call, short ITM put	You take delivery — shares arrive in your demat
Short futures, short ITM call, long ITM put	You give delivery — you must hand over shares

Look at that second row. Short ITM call — that's an extremely common position. If you sold a call on a stock and it finished in-the-money, you are required to deliver those shares.

If the option expires out-of-the-money, nothing happens. It expires worthless, no delivery, no obligation. This only bites on ITM.

And if you have to deliver shares you don't own?

That's called short delivery. The exchange then buys the shares on your behalf in a special auction — and that auction price can be well above the normal market price. You pay the difference. It's a genuinely expensive way to find out about a rule.

You have two ways to avoid it:

1. Buy the shares in the cash market and deliver them.
2. Borrow the shares through SLB and deliver those.

That second option is why SLB matters to option sellers. It's the escape hatch. A bigger, cheaper lending market means that escape hatch works for more stocks, at a lower cost.

So why doesn't everyone just use it?

Because right now, the lending market in India is small. Three plain reasons:

1. Most stocks aren't eligible. Only around 176 stocks currently qualify for SLB — out of roughly 2,700 listed on NSE. That's about 7%. If the stock you're short isn't on that list, borrowing simply isn't an option.

2. Borrowing is expensive. To borrow shares you must post collateral — money parked as security. In India that's roughly 125–130% of the value of the shares you're borrowing. In the US and Europe it's closer to 100%. That extra 25–30% is dead capital, and it makes borrowing costly enough that many people don't bother.

3. Some of the biggest potential lenders can't fully participate. Mutual funds hold enormous quantities of shares doing nothing — the natural supply for a lending market. But rules limit their participation, which keeps supply thin.

Add it up and you get a market that's been around since 2008 but never really took off. SEBI's own framing is that the segment is significantly underdeveloped compared to other countries.

Worth saying clearly: India's derivatives market is one of the largest and most sophisticated in the world. The lending plumbing underneath it just never grew to match. That's the gap SEBI is trying to close — not by shrinking anything, but by building up the part that lagged.

What SEBI is actually planning

A consultation paper, coming soon. A working group is already formed. Nothing is final — the point of a consultation paper is to publish proposals and collect feedback first.

Reported to be under discussion:

• Expanding the list of eligible stocks
• Net settlement — within SLB, and between SLB and the cash market. In simple terms: instead of settling every leg separately, offsetting positions cancel out, so you tie up far less capital.
• Interoperability between exchanges — borrow on one, use it on the other.
• Better linkage between the cash and derivatives markets
• A separate review of how securities are grouped for margin and collateral purposes

Some analysts expect the eligible list could roughly double, to around 350 stocks, and collateral to come down toward 100%. Those specific numbers are analyst expectations, not SEBI announcements — treat them as a sense of direction, not a promise.

Timeline: proposals are expected to be finalised around the end of 2026. So nothing changes on your screen this week, or this month.

The connection to the closing auction

Here's what makes this timely rather than routine.

SEBI didn't present SLBM reform on its own. The chairman raised it while discussing the Closing Auction Session (CAS) — the new end-of-day auction that went live on August 3, and that had a bumpy first two weeks.

His words: "SLBM improves CAS participation and that has been our goal."

The logic is simple once you see it. The main complaint about the new closing auction was thin participation — not enough orders in the pool, so a small number of orders could swing the closing price around. One reason professional participants couldn't show up properly is that they couldn't easily borrow shares to trade with.

So: make borrowing easier → more participants can join the closing auction → the auction pool gets deeper → the closing price gets steadier.

That's the plan. Fix the lending market to fix the auction.

What this means for you as an options trader

Straightforwardly good, in three ways.

1. A better safety net at expiry. More eligible stocks and cheaper borrowing means the SLB route out of a delivery obligation is available in more names, at lower cost. If you sell stock options, that's a real improvement to your worst-case scenario.

2. A steadier settlement price. Your stock F&O contracts settle against the underlying's closing price — which now comes out of the closing auction. A deeper auction produces a less erratic price. That's the number your position settles against.

3. Potentially better pricing in stock options. Market makers quote tighter when they can hedge cheaply. Borrowing shares is part of how they hedge. Cheaper borrowing tends to show up as tighter bid-ask spreads — which is money, on every fill.

And a fourth, if you hold shares long term: lending out idle holdings for a fee becomes more practical as the market grows. Your shares keep sitting in your demat either way; this way they earn something.

It's also worth being clear about what this is not. SEBI's stated aim is interlinkage between the cash and derivatives markets — connecting them better. The chairman's framing is about improving price discovery and deepening the cash market, not restricting derivatives. Nothing here reduces what you can trade.

FAQ

Is SLBM new? No. It's been running since 2008. The short-selling framework alongside it dates to 2007 and hasn't been revised since. What's new is that SEBI is rewriting both.

Has anything changed yet? No. A consultation paper hasn't even been published. Proposals are expected to be finalised around end-2026, and implementation would follow after that.

Does this affect Nifty and Bank Nifty options? Not directly. Index options are cash-settled — no shares are ever delivered, so the physical-settlement issue doesn't arise. The indirect benefit is a healthier, deeper cash market underneath the index.

Can retail investors use SLB today? Yes, in principle, for eligible stocks — many brokers support it, though sometimes through an offline process rather than in the app. Check with your broker.

If I lend my shares, do I still own them? Yes. You're renting them out, not selling them. The clearing corporation guarantees the return, which is the key protection.

I sell stock options. What should I actually do? Nothing new because of this announcement. But it's worth knowing your delivery obligation before expiry week — specifically, whether you're short an ITM call on a stock, and whether that stock is SLB-eligible. That's useful today, regardless of what the consultation paper eventually says.

---

This article is general market-structure education, not investment advice, and FNODATA is not a SEBI-registered investment adviser. It is not a recommendation to buy, sell, or hold any security or derivative contract. Proposals described here are at consultation stage and may change. Eligible-stock counts, collateral percentages and timelines are as reported in mid-August 2026 — confirm current rules against SEBI circulars, the exchanges, and your broker.