NISM Professor

Option premium

Also written Premium · Option price

The price an option buyer pays the seller for the right the contract carries — non-refundable, and made up of intrinsic value plus time value.

In plain language

An option gives its buyer a right and no obligation; the seller takes on an obligation and no right. That asymmetry has to be paid for, and the payment is the premium.

It changes hands up front and it is non-refundable. Whatever happens afterwards, the buyer's maximum loss is the premium, and the seller's maximum gain is the premium.

Nobody sets it. The workbook is blunt on this point: premiums are not fixed by the exchange or by SEBI — they are discovered by buyers and sellers, exactly as futures prices are.

How it works

Premium splits into two parts, and only one of them can be computed from today's prices:

Premium = Intrinsic value + Time value

Intrinsic value is the amount by which the option is in the money: S - X for a call and X - S for a put, floored at zero. It is never negative, so at-the-money and out-of-the-money options have none.

Time value is the rest. It exists because the option has not expired yet, and it decays to zero by expiry — non-linearly, accelerating as expiry approaches. This is why options are called wasting assets, and why the workbook notes that option sellers hold a fundamental advantage: one of the two components is inherently biased downwards.

Five variables drive the premium:

Factor risesCall premiumPut premium
Price of the underlyingRisesFalls
Strike priceFallsRises
Time to expiryRisesRises
VolatilityRisesRises
Interest rateRisesFalls

The formula

Premium = Intrinsic value + Time value

Intrinsic value of a call = max(Spot - Strike, 0)
Intrinsic value of a put  = max(Strike - Spot, 0)
Time value                = Premium - Intrinsic value

A worked example

The workbook's zinc option. Strike Rs 180, call premium Rs 10, put premium Rs 8, one month to expiry.

At expiry, per unit:

Market priceCall buyerCall sellerPut buyerPut seller
220+Rs 30−Rs 30−Rs 8+Rs 8
200+Rs 10−Rs 10−Rs 8+Rs 8
160−Rs 10+Rs 10+Rs 12−Rs 12
140−Rs 10+Rs 10+Rs 32−Rs 32

Read the call column downwards. Below Rs 180 the call buyer's loss stops at Rs 10 however far the market falls — the premium, and nothing more. The call seller's gain stops at the same Rs 10 however far it falls.

Now split a live premium. A commodity future is at Rs 1,280, and an option on it quotes a premium of Rs 200 against a strike of Rs 1,150:

Intrinsic value = 1,280 - 1,150 = Rs 130
Time value      = 200 - 130     = Rs  70

Rs 70 of that Rs 200 is being paid purely for time remaining, and it is gone by expiry even if the future never moves.

Why NISM asks about it

Chapter 4 (Commodity Options), section 4.2 for the terminology and section 4.4 for the determinants — the factor table above is reproduced almost verbatim in the workbook and is examined directly. Expect "split this premium into intrinsic and time value" arithmetic, a question on which way a rise in interest rates moves a put premium (down), and the payoff table logic that the buyer's loss is capped at the premium.

Common exam traps

  • The premium is not the strike price. The strike is the price at which the commodity changes hands; the premium is what the right to that strike costs.
  • Intrinsic value can never be negative. An out-of-the-money option has zero intrinsic value and its entire premium is time value.
  • Time to expiry raises both call and put premiums, unlike the underlying price, which moves them in opposite directions.
  • Time decay is not linear — it accelerates towards expiry, so a one-month option is worth considerably more than half a two-month option.
  • The premium is non-refundable. Letting an option lapse unexercised does not return it.
  • Rising interest rates lift calls and depress puts. Volatility, by contrast, lifts both.

Where this is taught

Free preparation for NISM Series XVI

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