The Rulebook Nobody Reads

Every casino has a pit boss watching the tables, not to stop you from playing, but to stop the house's own dealers from quietly handing out more chips than the vault can cover.

SEBI plays a similar role for Indian leverage — not to stop you from trading, but to stop your broker from handing you more exposure than the system can absorb if you're wrong.

The rules feel like red tape until the one day they're the only thing standing between a bad trade and a broker with no capital left to pay anyone.

Why margin requirements exist

Every leveraged position is, structurally, a loan. Someone — your broker, a clearing corporation, an exchange — is on the hook if you can't cover a loss. SEBI's margin framework exists to make sure that hook never becomes systemic: that one trader's blow-up doesn't cascade into their broker's collapse, which cascades into the clearing house, which cascades into everyone else's account.

That's why margin requirements aren't a single flat number. They move with volatility — a stock that's been swinging wildly gets a higher margin requirement than a sleepy blue chip, because the potential loss the system needs to cover is genuinely bigger.

SPAN, exposure margin, and peak margin — in plain terms

For futures and options, your broker collects margin in layers. SPAN margin is the base layer — a statistically modelled estimate of the worst one-day loss your position could plausibly take, calculated using standardised scenarios of price and volatility movement. Exposure margin sits on top of it as an extra buffer, because 'worst plausible day' still leaves room to be wrong.

Since 2021, SEBI's peak margin rules require you to have adequate margin in your account at any point during the trading day — not just at day's end — and brokers must report shortfalls to the exchange. Trade without covering an intraday margin requirement and you're not quietly getting away with it; the broker is penalised, and that penalty logic is exactly why brokers auto-square-off under-margined positions without waiting for your permission.

For MTF specifically

MTF margin is calculated using Value at Risk (VaR) plus a multiple of the Extreme Loss Margin (ELM) for the stock — broadly, a statistical estimate of how far the price could realistically move against you, with a safety multiplier on top. This is why the same ₹1,00,000 might buy you 4x exposure on a stable large-cap and barely 1.5x on a volatile mid-cap: the rule isn't arbitrary, it's the system pricing the stock's own risk into how much rope you get.

The framework is a floor, not a target

The single most expensive misreading of this chapter is treating the maximum leverage a broker or regulator allows as the leverage you should use. SEBI's rules set the ceiling the system can tolerate without breaking. They say nothing about what your account, your strategy, or your stomach can tolerate — that number is almost always lower, and it's the one this school spends the next several chapters helping you find.