Skip to content
All library documents

Valuing a Forward Contract at an Intermediate Time

Article Quant Q&A · Author: GHStein

Summary

The document discusses no-arbitrage valuation of an existing forward contract at an intermediate date. The worked setup calculates the forward price at inception from the spot price and the full-period financing factor, then recalculates the current forward price from the intermediate spot price and the remaining-period factor. The contract value is the discounted difference between those forward prices, with the discount factor covering only the remaining time to maturity.

The accepted numerical answer applies semiannual compounding to a one-year contract with a six-month point in time, producing a value of 20. Other responses emphasize checking compounding conventions and discount-factor direction: a discount factor should generally be no greater than one for a positive rate. The discussion contains some conflicting or incomplete replies, so the formulas and inputs should be checked carefully. Consistent compounding periods and the correct remaining-term discount factor are essential to avoid errors.

Key ideas

  • An intermediate forward value is based on the difference between the current forward price and the contract's original delivery price.
  • Compute the original forward price using financing over the full contract term.
  • Compute the current forward price using the intermediate spot price and financing over the remaining term.
  • Discount the forward-price difference over the remaining time using the stated compounding convention.
  • For a positive interest rate, a discount factor should be below one; verify whether a factor is a discount or accumulation factor.

Tags

Full text
# Simple value of a Forward contract at an intermediate time question


# Simple value of a Forward contract at an intermediate time question












I am taking "Financial Engineering and Risk Management Part I" from Columbia University on coursera and I got a seemingly simple question wrong on the first quiz. This is all based on the no-arbitrage arguments. Here is the question:

During the lesson we constructed a portfolio to try to get the value of a forward at an intermediate time. Here is what we got:

What was missing at this point was how to get F(t) and F(0). A few slides back we did:

Ok so now I have all of the ingredients for this forward soup. I got the forward price at time zero with the stock price at time zero divided by the discount for the whole period (two 6 month periods so its squared). Then I got the forward price at 6 months by taking the price at 6 months and dividing it by the discount for one six month period. I took the difference between the two and multiplied it by the discount factor for six months (between t and T). I ended up rounding off to 27. What am I doing wrong? Below is a picture of my calculations (I did not round any intermediate calculations). I'm more of a pencil and paper guy but if you want I can type it all up.

Also, Happy New Year to you all!

## Answer by QuantK (score 1, accepted)

https://quant.stackexchange.com/a/16053

Always take care that you got the compounding frequency right. I recommend you take a deeper look at http://breakingdownfinance.com/finance-topics/derivative-valuation/forward-contract/ . You can download an excel file here and take a deeper look at the formula. You can also give in the compounding frequency as input.

In case of doubt, or as a standard procedure, you could first start transform it to continuous compounding and use this to discount to avoid mistakes.

## Answer by Terminator (score 1)

https://quant.stackexchange.com/a/20818

Your discount factors are not inverted properly. Intuitively, df(0,T) should be a number between 0 and 1. For example, if r=0 then there is no discount so df = 1. If r > 0, then discount is going to be less than 1.

Your formula for df will always be greater than 1. Check the formula given by the prof on the last slide titled "Term structure of interest rates" for the PDF on linear pricing in week 2.

## Answer by Kiwiakos (score 0)

https://quant.stackexchange.com/a/16049

If we compound semi-annually and we have half year to go, then the current forward price is $$F = S \left(1+\frac{r}{2}\right) = 125 \left(1+\frac{0.10}{2}\right)$$ Isn't it as simple as that?

## Answer by Shivam Pundir (score 0)

https://quant.stackexchange.com/a/28201

Correct answer to the question is 20.

F_o= 100*(1+.1/2)^2=110.25 ....forward price at time 0(future value of 100 stock at time t=1 yr) F_t=125*(1+.1/2)=131.25 .....forward price at time t ( future value of 125 at time t=1/2yr down the line) d(t,T)=1/(1+.1/2)=.9523 f_t=(F_t-F_o)*d(t,T)=20

Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.