Why Derivative Timelines Need a Focal Date
A derivative position can involve cash flows on several dates: a premium at inception, periodic settlements, and a final payment or delivery. Adding amounts that occur at different times does not give a meaningful value. First place each amount on a timeline; then move all amounts to one focal date using a consistent set of discount factors.
This method is useful whether the contract is a forward, an option, or a swap. It does not by itself determine whether a contract is fairly priced. It organizes the cash flows and calculates their value under the discounting assumptions provided. For contingent contracts, a scenario or payoff rule must also be specified before the cash flows can be calculated.
Let \(C_j\) be a cash flow at time \(t_j\), with \(C_j>0\) for a receipt and \(C_j<0\) for a payment. Let \(D(0,t)\) be the discount factor from time \(t\) to time 0 on the specified curve. If the focal date is \(T\), the value of these cash flows at \(T\) is
This assumes the cash flows are expressed in the same currency and are discounted using the same curve and valuation basis. The formula works for cash flows before, on, and after \(T\): earlier flows are accumulated to \(T\), while later flows are discounted back to \(T\). If \(t_j=T\), the factor is 1. If \(T=0\), the expression is the usual present value \(\sum_j C_jD(0,t_j)\).
Why the Focal-Date Formula Works
A discount factor converts a value at a future date to its value at time 0. Therefore, the value at time 0 of a cash flow \(C_s\) at \(s\) is \(C_sD(0,s)\). If its equivalent value at a later date \(T\) is \(C_s A(s,T)\), where \(A(s,T)\) is the accumulation factor from \(s\) to \(T\), consistency requires
For a nonzero cash flow, divide by \(C_sD(0,T)\) to obtain \(A(s,T)=D(0,s)/D(0,T)\). The same ratio discounts a cash flow from after \(T\) back to \(T\); in that case it is less than 1 when discount factors decline with time. Summing the equivalent values of the individual flows gives the focal-date formula. This argument also shows why discount factors must come from one consistent curve: mixing incompatible factors can break the equivalence.
Forward Contract Cash Flows
For a long forward, the holder agrees to buy an underlying asset at the delivery date for the delivery price specified in the contract. At settlement, the long position receives the asset and pays the delivery amount. For a cash-settled equivalent, the net amount is based on the asset’s settlement value less the delivery price. Any separately agreed fee or interim adjustment belongs on its own date; it should not be hidden inside the maturity settlement.
Worked Example: A Forward With an Upfront Fee and Interim Adjustment
A hypothetical long forward covers 80 units of an asset and requires delivery at \(K=\$52\) per unit at time 1. The contract also requires a \(\$120\) fee at time 0 and pays the long party an interim adjustment of \(\$100\) at time 0.5. At time 1, the asset’s settlement value is \(\$55\) per unit. The discount factors are \(D(0,0.5)=0.98\) and \(D(0,1)=0.95\). Find the value of the position at time 1. Assume the stated settlement value applies, the fee and adjustment are certain, and all cash flows use the given curve.
Method. List the cash flows from the long party’s perspective. The time-0 fee is a payment of \(-\$120\). The interim adjustment is a receipt of \(+\$100\). At time 1, the long party receives an asset worth \(80(\$55)=\$4{,}400\) and pays \(80(\$52)=\$4{,}160\). The net settlement is \(+\$240\).
Use time 1 as the focal date. The time-0 fee accumulates by the factor \(1/D(0,1)=1/0.95\), and the time-0.5 adjustment accumulates by \(D(0,0.5)/D(0,1)=0.98/0.95\). Thus,
Rounded to the nearest cent, the position’s value at time 1 is \$216.84. As a check, its time-0 value is \(-120+100(0.98)+240(0.95)=\$206.00\); accumulating that amount to time 1 gives \(206/0.95=\$216.8421\), the same result. The common mistake this method avoids is counting the asset’s full value as a gain while forgetting the delivery payment, or leaving the fee at time 0 while adding it to time-1 amounts.
Option Premiums and Expiration Cash Flows
For a long call on one unit of an underlying asset, with strike price \(K\) and expiration value \(S_T\), exercise at expiration produces an asset worth \(S_T\) in exchange for a payment of \(K\). The resulting expiration value is \(\max(S_T-K,0)\): the holder can decline to exercise if doing so would require paying more than the asset is worth. A premium paid earlier is a separate cash flow. To compare it with the expiration amount, move it to the selected focal date rather than subtracting it as though it occurred at expiration.
Worked Example: A Call Premium Compared at Expiration
A hypothetical investor buys a one-year call on 100 shares, with strike price \(\$40\) per share, and pays a premium of \(\$2.50\) per share at time 0. At expiration, the share price is \(\$46\). The discount factor is \(D(0,1)=0.96\). Find the value at expiration of the premium and settlement cash flows together. Assume no other contract cash flows.
Method. The total premium paid at time 0 is \(100(\$2.50)=\$250\), so the signed cash flow is \(-\$250\). At expiration, exercising requires paying \(100(\$40)=\$4{,}000\) and provides shares worth \(100(\$46)=\$4{,}600\). The net expiration settlement is \(+\$600\). The call is exercised because \(\$46>\$40\).
At the expiration focal date, the time-0 premium accumulates by \(1/0.96\). Therefore,
Rounded to the nearest cent, the combined value is \$339.58. A cross-check at time 0 is \(-250+600(0.96)=\$326.00\), which accumulates to \(326/0.96=\$339.5833\). This calculation compares the premium and settlement at one date; it is not a claim that the premium is an expiration payment. A common error is to subtract \(\$250\) directly from \(\$600\), mixing time 0 and time 1.
Swap Timelines and Interim Settlements
A swap typically produces a sequence of settlement cash flows. For a party receiving a floating amount and paying a fixed amount, each net settlement is the floating receipt less the fixed payment on that date. Record the net amount with its sign, or list both legs separately and add them after valuing each. Do not insert an exchange of notional principal unless the contract actually specifies one; a notional amount is often used to calculate payments but is not itself exchanged.
Worked Example: Valuing a Swap at an Intermediate Focal Date
A hypothetical party receives floating payments and pays fixed payments under a swap. Its net settlements are \(+\$96\) at time 0.5, \(-\$50\) at time 1, and \(+\$75\) at time 1.5. It also paid a separate fee of \(\$24\) at time 0. The discount factors are \(D(0,0.5)=0.96\), \(D(0,1)=0.9216\), and \(D(0,1.5)=0.884736\). Find the value at time 1. Assume these net settlements and the fee are certain and there is no notional exchange.
Method. Use time 1 as the focal date. Move the first settlement forward using \(0.96/0.9216\), leave the time-1 settlement unchanged, and discount the time-1.5 settlement using \(0.884736/0.9216\). Accumulate the time-0 fee using \(1/0.9216\).
Rounded to the nearest cent, the time-1 value is \$95.96. To check, the time-0 value is \(-24+96(0.96)-50(0.9216)+75(0.884736)=\$88.4352\). Accumulating it to time 1 gives \(88.4352/0.9216=\$95.9583\). The common mistake avoided here is discounting the time-0.5 settlement back to time 0 even though the chosen focal date is time 1, or adding an unexchanged notional to the swap cash flows.
Common Timeline Errors
A timeline is most valuable when it makes assumptions visible. Before calculating, confirm the party whose perspective is being used, the exact date of each cash flow, and whether each amount is gross or net. Then apply the focal-date conversion consistently.
- Mixing signs. If a party receives the floating leg and pays the fixed leg, its net settlement is floating received minus fixed paid. Reversing the party’s perspective reverses every sign.
- Mixing dates. A premium paid now is not automatically an expiration-date amount. Move it to the focal date before combining it with later flows.
- Omitting a contract leg. A forward delivery includes both receipt of the asset and payment of the delivery price. An option exercise similarly involves acquiring the asset and paying the strike.
- Adding an amount that is not paid. A swap notional is not a cash flow merely because it appears in a payment calculation.
- Mixing curves or conventions. Use discount factors for all dates from the same specified valuation basis. If the problem supplies different curves for different cash flows, the valuation rule must say how those curves are to be applied.
When settlements are uncertain, the timeline still records their dates and signs, but additional assumptions are needed to determine their values. The calculations here take the stated cash flows as certain or as realized amounts in a specified scenario. They do not introduce a probability model for future prices or estimate a derivative’s fair value from uncertain payoffs.
Check Your Understanding
Use the stated discount factors and the receiving party’s perspective. Round money to the nearest cent.
- A position has cash flows of \(-\$40\) at time 0, \(+\$100\) at time 0.5, and \(-\$30\) at time 1. Given \(D(0,0.5)=0.97\) and \(D(0,1)=0.94\), find its value at time 1. (Answer: \(\$30.64\))
- A long forward covers 25 units, has delivery price \(\$18\) per unit, and settles when the asset is worth \(\$20\) per unit at time 1. The long party paid a \(\$15\) fee at time 0 and receives a \(\$20\) adjustment at time 0.5. Given \(D(0,0.5)=0.99\) and \(D(0,1)=0.96\), find the time-1 value. (Answer: \(\$55.00\))
- A hypothetical investor pays \(\$1.20\) per share at time 0 for a one-year put on 40 shares with strike price \(\$30\). At expiration the share price is \(\$26\), and \(D(0,1)=0.95\). Find the combined value of premium and settlement at time 1. (Answer: \(\$109.47\))
- A swap party’s net settlements are \(+\$60\) at time 0.5, \(-\$20\) at time 1, and \(+\$40\) at time 1.5, and it paid a \(\$10\) fee at time 0. Given discount factors \(0.98\), \(0.95\), and \(0.92\) at those three settlement dates, respectively, find the value at time 1. Assume there is no exchange of notional. (Answer: \(\$70.11\))