I'm a bit confused about the definition of contract notional value for a futures contract. It is not defined in John Hull's Options, Futures, and Other Derivatives. I find two definitions online. Both have a lot of sources:
Futures price $\times$ contract size
Spot price $\times$ contract size
Some even use one definition in the formula or definition, but use the other definition as a numerical example:
Similarly, in CFA Level 3 curriculum (May 2022),
- In Reading 9 about Swaps, forwards, and futures strategies, Section 8.1, the first definition is used. It writes
Once the notional values to be traded are known, Rossi determines how many futures contracts should be purchased or sold to achieve the desired asset allocation. The FTSE MIB Index futures contract has a price of 23,100 and a multiplier of €5, for a value of €115,500. The DAX index futures contract has a price of 13,000 and a multiplier of €25, for a value of €325,000.
- In Reading 11 about fixed-income portfolio management, Section 7.2.1 about using futures for leveraging fixed income portfolio, the second definition is used. It writes
A futures contract’s notional value equals the current value of the underlying asset multiplied by the multiplier, or the quantity of the underlying asset controlled by the contract.
So I'm shocked by the divergence of opinions. Personally, I think the first one makes more sense since its daily changes is used for mark to market and it is also used to calculate the hedge ratio, e.g. in cross-hedging. I don't know why the second definition pops out.