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

A trader leaves the default tax regime once, and the way back is a door that welds shut behind them

Almost everything written about the two regimes is written for a salaried reader, and for that reader it is broadly right: compare the two numbers each year and take the smaller. For a trader it is wrong in a way that cannot be undone, because the statute puts a taxpayer with business income into a separate class with a separate rule, and a derivatives book produces business income from the first contract.

The rest follows from that misfiling. Traders are told the default regime removes their expenses, which it does not, and handed break-even tables built on levers a full time trader does not have.

Two ladders, and what each one is buying

The default regime, long numbered section 115BAC, is a longer and shallower slab ladder. Nothing is charged below 4,00,000, the rungs rise in four lakh steps, and the top rate arrives only above 24,00,000. It carries a rebate of up to 60,000 within a total income of 12,00,000, and caps the highest surcharge at 25 percent rather than 37.

The old regime is the residual. Its exempt band ends at 2,50,000, it reaches 20 percent at 5,00,000 and the top rate at 10,00,000, and its rebate runs only to 5,00,000. In exchange it carries almost the whole deduction apparatus: investment and insurance, interest on borrowed capital for house property, rent paid without a house rent allowance, the individual pension contribution and the rest of Chapter VI-A. Which side costs less is arithmetic that depends on what the taxpayer can evidence.

The gap is structural rather than marginal. The old ladder finishes climbing at 10,00,000; the default ladder needs another 14,00,000 to reach the same place. Across that band a taxpayer with few deductions pays materially less in the default regime, and that band is where most independent traders sit.

The choice does not reach into the business computation

This is the correction that matters most, and generic pages never make it. A trader who reads that the default regime disallows deductions concludes that it disallows their costs. It does not, and the distinction is structural.

Business income is computed first, under the head profits and gains of business or profession. Brokerage, exchange and clearing charges, Securities Transaction Tax where the income is business income, depreciation on equipment, data and platform costs, interest on capital borrowed for the business, accountancy and audit fees are all subtracted under sections 30 to 37 in arriving at the profit. Only then is gross total income assembled, and only then does Chapter VI-A operate. The regime choice sits at that second stage and does not reach back into the first.

Two things in the default regime do touch the business computation. Additional depreciation and the specified business deductions are unavailable, which matters to a manufacturer and almost never to a trader. More relevantly, a loss under the head house property cannot be set off against business income there, so a trader sheltering trading profit behind a let out property's loss loses that shelter, and interest on a self occupied property goes with it.

The asymmetry, and why it is the whole article

The provision allowing a taxpayer to leave the default regime distinguishes two classes of person and gives them different rights.

A person with no income from business or profession exercises the choice in the return itself, for that year alone. There is no form, nothing accumulates, and the decision has no memory.

A person with income from business or profession exercises the option through Form 10-IEA. Having exercised it they may withdraw it only once, and only for a year other than the year of exercise. After that they are never again eligible to exercise the option, subject to one exception below. Two moves in total, not two moves a year.

Read the two moves precisely, because the usual shorthand loses the shape. Move one is leaving the default for the old regime, which then continues year after year with no refiling. Move two is the return journey, and it is the withdrawal the statute permits once. After move two the mechanism for leaving is spent.

The risk across the two is therefore not symmetric. Move one can be undone, once. Move two is terminal, and it is the one people make casually, because returning to the default feels like reverting to normal rather than spending a right. A trader who opts out in a year of heavy insurance and loan payments, then drifts back two years later because the default was marginally cheaper, has closed the door on every future year in which the old regime would have been better.

The form, the deadline, and the year that cannot be recovered

Form 10-IEA is filed electronically and carries both directions of travel. It generates an acknowledgement number, quoted in that year's return and carried into later returns while the option continues.

The deadline is the part that costs money. The form must be filed on or before the due date for furnishing the return under section 139(1). For a person with business income that date is later than the salaried one, and later again where accounts must be audited, but what governs is whatever the section 139(1) date is in that year, and extensions move the form's deadline with it.

Missing it does not delay the choice, it removes it. A late return under section 139(4) does not cure a late form, because the form is tied to the section 139(1) date rather than to the date of actual filing. Income is computed under the default regime, the deductions claimed are disallowed on processing, and a demand follows. Revising the return does not change the regime, and rectification is not the route either. The mirror of that is a trader who intends to stay in the default regime, who files nothing at all, because every obligation here attaches only to leaving and to coming back.

Where the crossing point actually sits

The break-even is the level of deductions at which both regimes produce the same liability. Below it the default regime costs less; above it the old regime does, and it is not a single number.

Compute it in two steps. Tax the total income under the default ladder with no Chapter VI-A deductions, then solve for the deduction level that produces the same tax under the old ladder on the reduced income. The gap between that figure and what the taxpayer can evidence is the answer.

Two features of that table decide most cases. Below roughly 12,00,000 the rebate takes the default liability to nil, so the old regime can only match it and never beat it. Above 24,00,000 the break-even flattens at 7,75,000, because both taxpayers are then in a 30 percent band and every further rupee is taxed identically in each.

Now the part the salaried tables hide. The two largest levers in the old regime are the standard deduction and the house rent allowance exemption, and both are constructs of the salary head. A trader with no employment income has neither, in either regime.

That is why published comparisons mislead independent traders. A salaried reader starts with 75,000 of standard deduction and often a substantial rent exemption before any voluntary saving. A trader starts at zero and builds the whole stack out of Chapter VI-A, which caps out short of the crossing point unless a house loan of size sits behind it. That decides no particular case. It says where the burden of proof lies, before a move is spent.

The rebate does not reach a trader's capital gains

One more asymmetry, specific to a reader whose income mixes business profit with capital gains. The rebate in the default regime is generous on slab rate income and does not touch income charged at special rates.

From assessment year 2026-27 this is express. Tax on short term gains under section 111A and long term gains under section 112A is computed separately from tax on slab rate income, and the rebate applies only to the second. A trader with business profit inside the rebate band and a large short term gain alongside it cannot shelter the gain by staying under the threshold, because the threshold governs eligibility while the rebate reaches only the slab rate portion.

The year a salaried reader crosses into the restricted class

The restriction attaches to the person having business income, not to the person being a full time trader, which produces a transition most explainers omit. An employee who has been choosing freely between the regimes for years opens a derivatives account. From the first year that book produces business income the annual choice is gone, and an action taken casually every year since they started working now consumes a right that does not renew.

They also acquire a filing obligation they did not have. Choosing the old regime, previously a box in the return, now needs Form 10-IEA by the section 139(1) date, and a reader who has never filed that form is the one most likely to miss it. The character of that income and the turnover figure that follows are in the guide to how derivatives income is taxed, and the presumptive route in the guide to presumptive taxation for traders.

What resets the restriction, and what does not

The statute provides one route back. Where the person ceases to have any income from business or profession, the annual choice becomes available again, because they have moved into the unrestricted class. For a trader that is meaningful but narrow. A year in which the account produces only capital gains, with no derivatives and no intraday activity, is a year with no business income. A year with a single derivatives trade is not. The test is the existence of business income rather than its size, and it turns on what the records show rather than on what was intended.

What does not reset it: changing the nature of the trading, because derivatives and intraday are both business income; a loss, because a loss is still income from business here; the presumptive scheme, because it computes business income rather than removing it. A failed opt-out, where the form was late and the default applied, is a year taxed on the wrong basis rather than a move spent.

Running the decision in order

One. Compute business income, then pull out special rate income. Any derivatives or intraday activity in the year puts you in the restricted class. Every cost of running the book is deducted at this stage in both regimes, and gains charged at special rates are taxed outside the slab ladder in both, so they leave the comparison before it starts.

Two. Compute the default liability with no Chapter VI-A deductions, then solve for the break-even. The first figure is the benchmark and is also what applies if you do nothing. The second is what the rest of the decision turns on.

Three. Count only deductions you can evidence today. Not what could be invested before March. A deduction needing a payment not yet made is a plan, and a plan is a poor reason to spend a move that does not renew.

Four. Price the move across every remaining year, then file on time. A year that favours the old regime modestly is a weak reason to spend a right that cannot be rebuilt. If you are leaving, the form goes in by the section 139(1) date, before the return and never after it.

Where this goes wrong in practice

Believing the default regime disallows trading costs. Those are business expenses computed before the regime question arises, so the confusion pushes traders out of a regime that was costing them nothing on that account.

Spending the return move carelessly. It is the move that closes the door, and it is made less deliberately than the move that opens it.

Filing the form with the return, or treating a loss as a way out. The deadline is the section 139(1) date and a belated return does not carry it along. The restriction follows the existence of the source, not its result.

What the choice is actually for

These are two bargains offered to the same taxpayer, and the legislature made one the default because it expects most people to take it. It is a choice between a rate structure and a deduction structure, and which is cheaper depends on facts only the taxpayer can evidence.

What is asymmetric is the cost of being wrong. A salaried reader who misreads the comparison loses one year and corrects it in the next. A trader who misreads it spends a right that does not renew, in a year that may not represent the ten that follow. That is why the answer here is a method and a threshold rather than a recommendation. The gain and loss side of the same arithmetic is in the guide to short and long term gains for an active trader.