Gross Profit and Loss, Explained: What Sits Between Gross and Net

Gross profit and loss is the raw result of your positions: exit value minus entry value, before anything is deducted. Net profit and loss is what actually lands in the account after every charge along the way. The distance between the two is made up of brokerage, statutory taxes, exchange and regulator charges, GST, slippage, and any financing cost, and for an active strategy that distance can be the difference between a result worth having and one that is not.

Almost every dispute about whether a strategy “works” turns out, on inspection, to be a dispute about which of these two numbers is being quoted.

What each one measures

Gross P&L is arithmetic on prices. For each closed position, take the exit price, subtract the entry price, multiply by the quantity, and sum across all positions. Reports usually split it into two halves. Gross profit is the total from positions that ended positive. Gross loss is the total from positions that ended negative. Their sum is gross P&L, and their ratio is the profit factor.

Net P&L is gross P&L minus everything else. In the Indian equity market, the items between the two typically include:

• Brokerage. Charged by the broker, either as a percentage of turnover or a flat fee per order, on both the buy and the sell.
• Securities Transaction Tax. A statutory tax on transactions in listed securities, with different treatment for delivery-based and intraday trades and for the buy and sell legs.
• Exchange transaction charges. Levied by the exchange on turnover.
• SEBI turnover fees. A small regulator charge on turnover.
• Stamp duty. Charged on the purchase leg, at rates set under the applicable stamp duty framework.
• GST. Applied on the brokerage and on certain of the charges above, rather than on the trade value itself.
• Depository and demat charges. Typically applied on the sale of delivery holdings.
• Slippage and market impact. Not a fee, but a real cost: the difference between the price your model assumed and the price your order actually achieved.
• Financing and borrow costs, where leverage or short exposure is involved.

Rates and applicability change over time and differ by instrument, segment and broker, so this article deliberately quotes no numbers. The structure is the point. What matters is that most of these are charged on turnover, not on profit, which means they are incurred whether the trade worked or not.

How to read it

First, establish which number you are looking at. A report that says “total profit” without qualification is usually gross. If the tool exposes a cost setting, look at what it was set to. A cost assumption of zero is a modelling choice, not a neutral default, and it flatters exactly the strategies that trade the most.

Second, size the gap by round trips, not by percentage of profit. The correct mental model is: cost equals cost per round trip multiplied by the number of round trips. A strategy that turns its portfolio over a handful of times a year and one that turns it over weekly face the same per-trade charges but wildly different totals. This is why portfolio turnover is not just an operational statistic, it is a cost statistic.

Third, notice that costs attack profitability from both directions. They shrink every winner and enlarge every loser. That means the move from gross to net worsens the numerator and the denominator of profit factor simultaneously, drags down the average trade, and pushes marginal winners across the line into the loss column, which lowers the win rate too. A single cost assumption changes almost every statistic in the report at once. This is the reason net and gross versions of the same strategy can look like two different strategies.

Fourth, check whether slippage was modelled at all. Brokerage and taxes are the easy part, because they are formulaic. Slippage is the hard part, because it depends on order size relative to the traded volume, the spread, and how urgently the order was pushed into the book. Many reports include statutory costs and quietly assume perfect fills at the closing price, which is the single most common way a backtest overstates itself.

Fifth, ask whether taxes on gains are inside or outside the number. Transaction taxes such as STT are charged at the point of trade and are usually included in net P&L. Capital gains tax is charged on realised gains and is normally left out of strategy reports entirely, because it depends on the holder’s circumstances. That is a defensible convention, but it means “net” in a report is not the same as “net in your hands”.

A useful discipline: never compare two strategies unless both are quoted on the same basis. Gross against net is not a comparison, it is a category error.

What it does not tell you

Gross P&L does not tell you whether the strategy is viable. That is its defining limitation. Gross is a statement about the idea. Net is a statement about the business of running the idea. An idea can be sound and the business unviable, and gross P&L cannot distinguish those cases.

Net P&L does not generalise across users. Brokerage plans differ, order sizes differ, and execution quality differs. A net figure computed under one set of assumptions is not automatically the net figure another investor would have achieved. Net is always net under stated assumptions, and those assumptions should be visible.

Neither number tells you about the path. Both are totals. They say nothing about how long the strategy spent underwater, how deep the worst fall was, or in what order the results arrived. For that you need maximum drawdown and the underwater history.

Neither tells you about capital or time. A rupee total means nothing without knowing how much capital was committed and for how long. Return measures such as CAGR exist precisely because totals do not answer that question.

Costs modelled as a fixed percentage understate the tails. Real execution cost is not constant. It rises when liquidity is thin, when the position is large relative to normal volume, and when markets are moving quickly, which tends to be exactly when a strategy wants to trade. A flat assumption smooths away the worst cases, so even a carefully “net” backtest can be optimistic at the moments that matter most.

And costs are certain while profits are not. This asymmetry deserves stating plainly. The charges will be incurred on every trade, whatever happens. The gross profit is a hypothesis about the future that may or may not hold. Any framework that treats a certain cost and an uncertain gain as equally solid is misleading itself.

The practical takeaway is unglamorous but reliable. When you open a strategy report, find the cost assumption before you look at anything else, and if you cannot find it, treat every number in the report as a gross number until proven otherwise.

Related reading

• Portfolio and Backtest Metrics, Explained: the hub guide to the metrics in a strategy report, and what each conceals.
• What Is Profit Factor: gross profit divided by gross loss, and how costs change it from both sides.
• Portfolio Turnover, Explained: what drives turnover and why it multiplies every per-trade cost.
• Transaction Costs in Backtests: the specific charges and how they are modelled.
• Slippage and Impact Cost: the cost that is not a fee, and the one most often ignored.

This article is educational. Altys Labs is not a registered research analyst or investment adviser, and nothing here is investment advice or a recommendation to buy, sell, or hold any security.