Exchange Rate Arithmetic: Forward Rates
Forex dealers normally quote forward
rates at regular intervals like one month or three months. For example, dealers
normally quote 1-week, 2-week, 1,2,3 6 months forward rate. However, depending
on customer’s requirement, these delaers quote forward rate on a specific
future date that is not an exact multiple of months. Such kinds of forwards
quotes are known as broken period quotes.
Banks normally quote broken period
rates by method of interpolation. Let us take an example to understand this.
On July 14th the following rates are quoted by a bank as
given in Table 15.1. However a
corporate customer wants to buy 100,000 USD on October 21st. The bank has to quote a forward rate for
this date.
Table 15.1: Cash/Swap rates in points
|
|||
USDINR
|
Maturity Date
|
Bid Rate
|
Ask Rate
|
Spot
|
July 14th
|
47.0725
|
47.0745
|
1 Month
|
August 14th
|
135
|
130
|
2 Month
|
September 14th
|
140
|
133
|
3 month
|
October 14th
|
160
|
145
|
4 months
|
November 14th
|
175
|
155
|
The
interpolation method is used as
follows:
•
The forward rate
points applicable are (160 to 175) for bid and (145-155) for ask.
•
For
31 days (October 14th to November 14th), the bid spread is 15 points (175 to 160).
• For 7 days, the spread in bid point = 1531
∗ 7 =
3.89
. So the spread applicable for October 21st
is 160 + 3.89 = 163.89
• Similarly, for 31 days (October 14th
to November 14th), the ask spread is 10 points (155 to 145).
For 7 days, the spread in bid point = 1031
∗ 7 =
2.26
. So the spread applicable for October 21st
is 145 + 2.26 = 147.26
•
The applicable bid
rate for 31 days (October 14th to
November 14th), the ask
spread is 15
points (175 to 160). For 7 days, the spread in ask point = 1531
∗ 7 =
3.89
. So the ask spread applicable for October 21st
is 160 + 2.26 = 163.89
•
So the applicable
bid rate will be = 47.0725 - 0.014726 = 47.0577.
•
Ask spread is =
47.0745- 0.016389=47.0581.
Table 15.2:
Interpolated Bid-Ask Spread ( USDINR)
Maturity Date
|
Bid Rate
|
Ask Rate
|
October 21st
|
47.0576
|
47.0581
|
For a forward contract maturing on
October 21st, the bank would quote a rate
(47.0576-47.0581) given in Table 15.2.
As the company wants to buy USD 100,000, the bank will offer USD at a rate of
INR 47.0581. If the company would like to sell USD, then applicable rate would
be INR 47.0576.
As forward contracts are OTC contracts,
in real life, most of the contracts would be for a broken periods.
15.3: Premium & Discount on Forward
Quotations:
Forward quotations can be expressed as
percentage premium or discount to the spot rate. Table 15.3 details the forward quotations expressed as percentage
premium/discount to forward
quotations.
Table 15.3 Forward Quotations in Outright and
Percentage form
USDINR
|
Outright Quotations
|
USD
|
Percentage
|
|
Premium/Discount (*)
|
||||
Bid Rate
|
Ask Rate
|
Bid Rate
|
Ask Rate
|
|
Spot
|
47.0725
|
47.0745
|
||
1 week
|
47.0750
|
47.0775
|
0.28%
|
0.33%
|
2 weeks
|
47.0795
|
47.0835
|
0.40%
|
0.52%
|
1 month
|
47.0840
|
47.0890
|
0.29%
|
0.37%
|
2 months
|
47.0900
|
47.0965
|
0.22%
|
0.28%
|
(*) : Annualized premium/discount
The forward rate (1 week) is expressed
as a percentage premium/discount in relation to spot in the following manner.
Compared to spot and 1 week forward, forward bid price of USD is more
expensive by 0.0025.
% Pr emium / Discount =
|
n
day forward bid − spot bid
|
*
|
365
|
*100
|
||||
n
day forward rate
|
||||||||
spot bid
|
||||||||
=
|
47.0750 − 47.0725
|
*
|
365
|
*100 = 0.28%
|
||||
47.0725
|
7
|
|||||||
The
above equation indicates that forward 1 week USD is at premium.
Similarly % premium/discount in forward
ask rate (1 week) can be
calculated in the
above
manner by comparing 1 week ask rate with the spot ask rate.
As the forward rates (for different
maturities) are higher than the spot rates, the forward rates are at a premium. In other words, as USD is expected
appreciate (as INR is expected to
depreciate), forward USD is at premium.
To find out the % premium/discount of
INR, we need to find out the bid-ask spread with INR as base currency. Table 15.4 lists the INRUSD bid-ask
spread.
Table 15.4 Forward Quotations in outright and
percentage form
As the forward rates (for different
maturities) are lesser than the spot rates, INR is expected to depreciate as
USD is expected to appreciate). Hence, forward INR is at discount to USD.
To sum up, when forward quote/variable currency appreciates (depreciates), the
base currency is at discount (premium).
15.5 : Factors affecting forward rates.
By now, we are familiar with the
intricacies of bid-ask quotations, broken period quotation, forward rate
premium/discount aspects. But how do the banks/dealers quote these forward
rates? What factors do they take into consideration for quoting a forward rate.
Besides supply, demand factors, the
most important factor which governs the forward point quotation is the prevailing interest rates in two
currencies.
I
|
v
|
− I
|
B
|
D
|
|||||||||||
Spot
*
|
*
|
||||||||||||||
360
|
|||||||||||||||
Forward point =
|
100
|
||||||||||||||
I
|
B
|
D
|
|||||||||||||
1 +
|
*
|
||||||||||||||
100
|
360
|
||||||||||||||
Where:
S = spot rate
IV = Interest rate in Variable/Quote/Term currency IB = Interest rate in Base currency.
D=
Actual No. of days between the spot and forward date.
360= No. of days in year. Different countries
use different day count conventions. It can also be 365.
If the forward point is positive, it is added
to the spot rate otherwise, it is subtracted form the spot rate.
Let us take an example to understand this
aspect: A bank wants to quote forward rate for 6 month from the spot date. The
details are
S
= Rs. 46.60/USD
IV = Interest rate in India is 8% per annum IB = Interest rate in US is 4% per annum. D=
182 days
360=
No. of days in year.
I
|
v
|
− I
|
B
|
D
|
||||||||||||
Spot
*
|
*
|
|||||||||||||||
360
|
||||||||||||||||
Forward point =
|
100
|
|||||||||||||||
I
|
B
|
D
|
||||||||||||||
1 +
|
*
|
|||||||||||||||
100
|
360
|
|||||||||||||||
8 −
4
|
182
|
|||||||||||||
46 .60 *
|
*
|
|||||||||||||
Forward point =
|
100
|
360
|
= 0.485= 48.5 points.
|
|||||||||||
4
|
182
|
|||||||||||||
1 +
|
*
|
|||||||||||||
100
|
360
|
|||||||||||||
Forward
point calculated in the above manner is also known as forward swap points.
Hence
the 6-month forward rate would be = 46.60 +0.485= INR 47.085/ USD
Now suppose, the interest rate in India is 3%
while in USA it is 5%. The forward point would be calculated as
3 −
5
|
182
|
|||||||||||||
46 .60 *
|
*
|
|||||||||||||
Forward point =
|
100
|
360
|
= -0.459= -45.9 points.
|
|||||||||||
5
|
182
|
|||||||||||||
1 +
|
*
|
|||||||||||||
100
|
360
|
|||||||||||||
Hence
the 6-month forward rate would be = 46.60 - 0.459= INR 46.141/ USD

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