European vs American Options

## The core difference An option's *exercise style* decides when the holder can convert the right into a position. A European option can be exercised only on the expiry date. An American option can be exercised on any trading day up to and including expiry. Both can still be *bought and sold* in the market any time before expiry — the difference is purely about when you can claim the underlying.

## How it works on Indian exchanges This distinction is very practical on the NSE. Index options — Nifty 50, Bank Nifty, FinNifty and Sensex options — are European style. Single-stock options, such as those on Reliance or HDFC Bank, are American style, meaning a holder could in theory exercise an in-the-money call early.

In reality almost everyone closes positions by trading rather than exercising, because exercising early throws away the option's remaining *time value*. Indian options are also cash-settled for index and STT-favourable for stocks (physical settlement applies to stock F&O at expiry), so traders rarely exercise manually at all.

## Why the style affects price Because an American option gives an extra right — early exercise — it can never be worth less than the equivalent European option, and is sometimes worth slightly more. The gap matters most for puts and for dividend-paying stocks, where exercising a call just before the ex-date can capture a dividend.

For most Indian retail traders the takeaway is simple: with Nifty and Bank Nifty you only get paid the intrinsic value at Thursday/weekly expiry, so don't expect to "cash out" early by exercising. With stock options you have flexibility but should weigh the STT on exercise (charged on the full settlement value, not just profit), which is exactly why brokers warn against letting in-the-money stock options expire unsquared.