Guide · Costs and taxes · Updated 2026-09-18

GST is the only trading cost with no way back, and the reason is a definition rather than a rate

Ask a shopkeeper what GST costs the business and the honest answer is nothing. It is charged on the way out, credited on the way in, and the difference remitted. A trader sits outside that architecture, not through an exemption, not through a carve-out written with traders in mind, and not because of anything a broker does. The reason is buried in two definitions written in 2017 that most cost pages never open. The stack itself is already decomposed line by line in the real cost of a trade in India. This page takes the one line that behaves differently and follows it to the end.

GST taxes the service of executing a trade, not the trade

The levy under section 9 of the CGST Act 2017 reaches supplies of goods or services, and everything else hangs off that. Section 2(52) defines goods as every kind of movable property other than money and securities. Section 2(102) defines services as anything other than goods, money and securities. Both carve securities out by name, leaving a securities transaction with no category to fall into, so the charging section never reaches it.

That is a stronger exclusion than it sounds. A transaction can sit outside the tax in several ways that are not equivalent: at a nil rate, exempted by notification, or listed in Schedule III as an activity treated as neither a supply of goods nor of services. Securities are in none of those buckets. They fail at the definition stage, before rate or exemption arises at all.

What remains inside the net is everything somebody supplies around the trade. A broker executes an order. An exchange provides matching and clearing. A depository holds and moves the securities. The regulator charges a turnover fee. Each is consideration for a service, so each is taxable.

The line down the middle of a contract note

Every contract note therefore splits into two halves governed by different statutes. The split is not by size, not by who collects the money, and not by whether the amount feels like a tax. It is by whether the line buys a service.

Most traders meet the consequence of the left column on a statement rather than in a rule. Brokerage is one of four taxable lines. Drive it to zero, as the flat-fee models do, and GST does not follow it down: the exchange charge, the SEBI fee and the depository charge remain, and 18 percent still lands on their sum.

Why the statutory levies escape, and why the usual explanation is wrong

Almost every page that raises this says Securities Transaction Tax is outside GST because you cannot tax a tax. The conclusion is right. The reasoning is not, and the difference matters to anyone defending a computation.

Section 15 of the CGST Act, which sets the value on which tax is charged, does the opposite of forbidding a tax on a tax. It expressly provides that the value of a supply includes taxes, duties, cesses, fees and charges levied under any law other than the GST laws, where the supplier charges them separately.

The actual mechanism is narrower. Securities Transaction Tax is not the broker's liability. It is the trader's, arising on the trader's own taxable securities transaction, and the broker collects and remits it on the trader's behalf. Stamp duty works the same way, as a liability of the buyer collected centrally through the exchange or the depository. Rule 33 of the CGST Rules handles exactly this pattern: where a supplier incurs expenditure as a pure agent of the recipient, on that recipient's authorisation, shows it separately on the invoice, and supplies it in addition to what it supplies on its own account, the amount is excluded from the value of its supply.

Hold the distinction, because it predicts the answer for a line nobody has told you about. A new charge is inside the base if it buys something an intermediary supplies, and outside it if the broker is merely collecting somebody else's levy. That test survives changes to the schedule. The slogan does not.

The credit chain, and the link that is missing for a trader

Input tax credit under section 16 of the CGST Act lets a registered person take credit of tax charged on supplies used in the course or furtherance of business. Read as the whole rule, that suggests any business expense carrying GST is recoverable. It is not, because credit is half of a mechanism. The other half is the output side: credit enters the electronic credit ledger and is then set off against tax payable on outward supplies. The ledger is a holding place, not a wallet.

For a trader the output side is empty by construction. Every other link is intact: the broker charges GST correctly and issues a proper tax invoice, and the expense is unambiguously incurred in the course of business. The credit still cannot be used, because the thing it exists to reduce does not exist.

Section 54(3) closes the last exit. Refund of unutilised credit is available in two situations only: zero-rated supplies made without payment of tax, and an inverted duty structure where the rate on inputs exceeds the rate on outputs. A trade is neither, so the 18 percent is final the way rent is final.

Registration does not unlock it

The natural next thought is to register, and the attempt carries a real compliance cost. Section 22 of the CGST Act requires registration once aggregate turnover crosses the threshold, 20 lakh rupees for services and 40 lakh for an exclusive supply of goods, halved in the special category states. Aggregate turnover is built from supplies, so trading turnover never enters the figure. A trader turning over several crore of notional in a year, with no other business, is not under the threshold. They are outside the test. Voluntary registration under section 25(3) changes nothing: the trader joins the compliance machinery while still making no outward taxable supply, so the credit accumulates with no liability to meet and no way to release it.

The fourth row is where the asymmetry lives. The broker recovers GST on its rent, software and audit fees, because it charges GST on what it sells. The trader recovers nothing, because what the trader sells is not a sale at all.

The trader who also runs a registered business, where the effect runs backwards

Here is the part almost no page on this subject reaches, and it reverses the intuition. A person running a GST-registered business who also trades securities through the same entity cannot credit the brokerage GST against the business output. That much is expected. What is not expected is that the trading actively destroys credit the business would otherwise have had.

Section 17(2) restricts credit where inputs are used partly for taxable and partly for exempt supplies. On its own that would not bite, because a trade is not an exempt supply either. It is not a supply. Section 17(3) closes the gap deliberately, providing that the value of exempt supply for this purpose shall include transactions in securities. It is a legal fiction with one narrow job: stopping a registered business from running large volumes of non-taxable income through shared overheads while claiming credit in full.

Applied to sale value that fiction would be brutal, because securities turn over at a scale no operating business matches. The Explanation in the credit rules supplies the calibration: a security is valued at one percent of its sale value. The reversal then runs through rule 42, in the ratio of exempt turnover to total turnover.

The left column is the law. The right is what the bare words of section 17(3) would produce without the Explanation, which shows what the one percent rule is doing: it is a relief inside a restriction, and the reason a business with a treasury book does not lose almost all of its overhead credit.

Net the position and the arithmetic is unambiguous. The GST on brokerage is borne in full, and on top of that roughly seventeen thousand rupees of credit the consultancy would have taken on rent, software and professional fees is reversed, purely because securities were sold from the same registration. Trading did not fail to produce a credit. It consumed one.

What a year of it actually costs

The rate is fixed, so the drag is set entirely by frequency. Take an illustrative index options round trip with one lakh rupees of premium turnover on each leg, at 20 rupees of flat brokerage per order. Brokerage across two orders is 40 rupees, the exchange transaction charge across both legs is about 71 rupees, and the SEBI turnover fee is 20 paise. The service base is about 111 rupees, and 18 percent of it is about 20 rupees. Twenty rupees is nothing, which is exactly why it is never examined. Run it at 40 round trips a month and the year looks different.

Set the middle row against the comparison that gives the page its point. A services business spending the same 53,405 rupees on inputs would have paid the same 9,613 rupees of GST and ended the year having borne none of it. The trader has borne all of it. Identical tax paid, opposite outcomes, and the only difference is which side of a definition their output falls on. The bottom row is not extreme for a systematic intraday book, and it stays invisible because it arrives twenty rupees at a time.

What the income tax computation gives back, and what it does not

There is partial relief, and its size is routinely overstated into a claim that the GST is recovered. It is not recovered. It is deducted. Where trading is taxed as business income, the GST on the service lines is an expense wholly and exclusively incurred for the business and reduces taxable profit. At a 30 percent marginal rate a rupee of unrecoverable GST costs 70 paise after tax instead of 100, which is real and is nothing like a pass-through, and in a loss year the relief is deferred. Where the income is capital gains, brokerage and the GST on it form part of the expenditure in connection with the transfer, or of the cost of acquisition, under section 48, which reduces the gain rather than the tax.

Two cautions. The income-tax numbers above carry their long-established 1961 numbering, which changed with the statute that replaced that Act from 1 April 2026, so check the current number before quoting one. The CGST Act 2017 is untouched by that renumbering, so every GST section on this page stands as written. Conflating the two is a live error in current commentary.

Second, which column applies is not chosen for convenience. Whether trading is business income or capital gains is a separate determination with its own criteria, worked through in how derivatives profits are taxed in India, and it governs the fourth row, where the treatment of Securities Transaction Tax flips.

Where this goes wrong in practice

Treating the GST line as recoverable because it always was elsewhere. Muscle memory from any other business says this number comes back. No filing, registration or structure changes that.

Registering under GST to claim it. The credit accumulates with nothing to discharge and no refund route under section 54(3). The trader acquires filing obligations and recovers nothing.

Running trading through an existing registered business. The most expensive version, because it converts a neutral outcome into a negative one under section 17(3) and rule 42.

Adding the GST into turnover. GST, like brokerage, is a cost of the business and not part of turnover for the audit and presumptive tests. Folding it in inflates the figure that decides both, as set out in the turnover computation guide.

Assuming a zero-brokerage account means no GST. Three of the four taxable lines survive it, and in the options segment the exchange charge is the largest of them.

What to do with this

Nothing here is negotiable, which makes it a planning input rather than a problem to solve. What remains is knowing its size and letting that size inform frequency. The 18 percent is a fixed multiplier on the service cost of trading, so every activity-driven cost is a fifth worse than the number most traders carry in their head. A strategy whose edge survives the raw stack but not the stack plus that multiplier has been measured against the wrong denominator.

Pull the annual figure once, from the actual statement rather than an assumption, and set it beside the year's result. Most traders have never seen those two numbers on the same page. It is the cheapest diagnostic in the cost stack, and the only one where the answer is guaranteed to be worse than the estimate, because the estimate assumes something comes back.