Fundamentals of Financial Instruments. Sunil K. Parameswaran
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СКАЧАТЬ m times per annum. In the earlier example, since HSBC was compounding on a monthly basis, m was 12. The effective rate of interest i is therefore given by

1 plus i equals left-parenthesis 1 plus r slash m right-parenthesis Superscript m

      We can also derive the equivalent nominal rate if the effective rate is given.

r equals m left-bracket left-parenthesis 1 plus i right-parenthesis Superscript 1 slash m Baseline minus 1 right-bracket

      We have already seen how to convert a quoted rate to an effective rate. We will now demonstrate how the rate to be quoted can be derived based on the desired effective rate.

      Assume that HSBC Bank wants to offer an effective annual rate of 12% per annum with quarterly compounding. The question is what nominal rate of interest should it quote?

      In this case, i = 12%, and m = 4. We have to calculate the corresponding quoted rate r.

StartLayout 1st Row 1st Column Blank 2nd Column r equals m left-bracket left-parenthesis 1 plus i right-parenthesis Superscript 1 slash m Baseline minus 1 right-bracket 2nd Row 1st Column Blank 2nd Column right double arrow r equals 4 left-bracket left-parenthesis 1.12 right-parenthesis Superscript 0.25 Baseline minus 1 right-bracket equals 11.49 percent-sign EndLayout

      Thus, a quoted rate of 11.49% with quarterly compounding is tantamount to an effective annual rate of 12% per annum. Hence HSBC should quote 11.49% per annum.

      Two nominal rates of interest compounded at different intervals of time are said to be equivalent if they yield the same effective interest rate for a specified measurement period.

      Assume that ING Bank is offering 10% per annum with semiannual compounding. What should be the equivalent rate offered by a competitor, if it intends to compound interest on a quarterly basis?

      The first step in comparing two rates that are compounded at different frequencies is to convert them to effective annual rates. The effective rate offered by ING is:

i equals left-parenthesis 1 plus 0.05 right-parenthesis squared minus 1 equals 0.1025 identical-to 10.25 percent-sign

      The question is, what is the quoted rate that will yield the same effective rate if quarterly compounding were to be used?

r equals 4 left-bracket left-parenthesis 1.1025 right-parenthesis Superscript 0.25 Baseline minus 1 right-bracket equals 0.0988 identical-to 9.88 percent-sign

      Hence 10% per annum with semiannual compounding is equivalent to 9.88% per annum with quarterly compounding, because in both cases the effective annual rate is the same.

left-parenthesis 1 plus r slash m right-parenthesis Superscript m upper N

      In the limit as m right-arrow proportional-to

left-parenthesis 1 plus r slash m right-parenthesis Superscript m upper N Baseline right-arrow normal e Superscript r upper N

      where e = 2.71828. Known as the Euler number or Napier's constant, e is defined by the expression:

normal e equals upper L i m Subscript n right-arrow infinity Baseline left-parenthesis 1 plus 1 slash n right-parenthesis Superscript n

      This limiting case is referred to as continuous compounding. If r is the nominal annual rate, then the effective annual rate with continuous compounding is er − 1.

      EXAMPLE 2.9

      Nigel Roberts has deposited $25,000 with Continental Bank for a period of four years at 8% per annum compounded continuously. The terminal balance may be computed as:

25 comma 000 times normal e Superscript 0.08 times 4 Baseline equals 25 comma 000 times 1.3771 equals dollar-sign 34 comma 428.19

      Continuous compounding is the limit of the compounding process as we go from annual, to semiannual, on to quarterly, monthly, daily, and even shorter intervals. This can be illustrated with the help of an example.

      EXAMPLE 2.10

      Sheila Norton has deposited $100 with ING Bank for one year. Let us calculate the account balance at the end of the year for various compounding frequencies. We will assume that the quoted rate in all cases is 10% per annum.

Compounding at Various Frequencies
Compounding Interval Terminal Balance
Annual 110.0000
Semi-annual 110.2500
Quarterly 110.3813
Monthly 110.4713
Daily 110.5156
Continuously 110.5171

      For instance, if we were to invest $P for N СКАЧАТЬ