Arbitrage, Replication, and Forward Pricing

How Level I tests no-arbitrage logic, replication, cost of carry, and forward contract pricing and valuation.

Once you know what contract family you are looking at, Derivatives becomes a no-arbitrage topic. Level I wants you to understand that derivative prices are anchored by replicating portfolios and the economics of carrying the underlying through time.

Why This Lesson Matters

Candidates often miss these questions because they:

  • memorize a pricing formula without understanding where it comes from
  • confuse forward price with forward value
  • mix spot price, expected future price, and no-arbitrage forward price
  • forget that carrying an underlying has a cost or benefit

The stronger reader asks which portfolio replicates the derivative payoff.

Arbitrage And Replication Are The Core Pricing Logic

ConceptWhat it meansWhy it matters
ArbitrageRiskless profit with no net investmentIf arbitrage exists, prices will not remain at that level
ReplicationBuilding the same payoff using other assetsEquivalent payoffs should have equivalent values under no-arbitrage

The exam often tests this in words before it tests it in formulas.

Cost Of Carry Explains Why Forward Price Differs From Spot Price

Forward price is not just a guess about where spot price will be later. It reflects the economics of holding the underlying until expiration:

  • financing cost
  • storage cost, if relevant
  • income or convenience benefits from holding the asset

That is why the no-arbitrage forward price can differ from the market’s expected future spot price.

For A Simple Non-Income Asset, Forward Price Comes From Carrying Spot Forward

For a basic one-period setup:

$$ F_0(T) = S_0(1 + r)^T $$

where (S_0) is spot price and (r) is the financing rate over the contract horizon.

The point is not just the algebra. If the forward price is too high or too low relative to this carry relationship, a cash-and-carry or reverse cash-and-carry arbitrage may exist.

Spot Price, Forward Price, And Expected Future Spot Price Do Different Jobs

Price conceptWhat it representsCommon trap
Spot priceCurrent cash-market price of the underlyingTreating it as if it already includes all carry through expiration
Forward priceContract price set today for future deliveryConfusing it with the contract’s value after initiation
Expected future spot priceMarket expectation of future cash-market priceAssuming it must equal the no-arbitrage forward price

Level I likes testing this distinction because many wrong answers sound intuitive but mix economic roles.

Forward Price And Forward Value Are Not The Same

At initiation, the forward contract price is set so that contract value is zero. Later, if market conditions change, the original contract can gain or lose value.

For a long forward on a non-income asset, a simple discrete-time expression is:

$$ V_t(T) = S_t - \frac{F_0(T)}{(1+r)^{T-t}} $$

If the market-implied forward price rises above the delivery price locked into your contract, the long position gains value.

Interest Rate Forward Logic Uses The Same No-Arbitrage Mindset

A standard forward-rate link is:

$$ (1+s_2)^2 = (1+s_1)(1+f_{1,1}) $$

The point is that two investment paths across time should be consistent. Level I may ask you to interpret the implied forward rate rather than treat it as a guaranteed future realized rate.

How CFA-Style Questions Usually Test This

  • by asking which arbitrage trade would exploit a mispriced forward
  • by testing whether the contract value is zero at initiation
  • by asking why forward price differs from spot price
  • by using a simple interest-rate forward setup or implied forward-rate relationship

Mini-Case

A candidate sees that the quoted forward price on a non-income asset is above the spot price and concludes the contract must be overvalued. That is too fast. A stronger answer asks whether the price difference is just the normal financing carry or a true no-arbitrage violation.

That is classic Level I design: the relationship matters more than the raw direction.

Common Traps

  • calling any forward price above spot “mispriced”
  • forgetting that forward value is zero at inception
  • assuming expected future spot and no-arbitrage forward price must be identical
  • treating implied forward rates as certain forecasts

Sample CFA-Style Question

What is the strongest reason a forward price on a non-income asset can exceed the current spot price without implying mispricing?

Best answer: The forward price can reflect the cost of financing the underlying until expiration, so a price above spot may simply reflect normal carry.

Why: Level I is testing whether you understand no-arbitrage pricing rather than naive price comparison.

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