货币时间价值英语.pptx

The Time Value of MoneyWhat is Time Value?We say that money has a time value because that money can be invested with the expectation of earning a positive rate of returnIn other words,“a dollar received today is worth more than a dollar to be received tomorrow”That is because todays dollar can be invested so that we have more than one dollar tomorrowThe Terminology of Time ValuePresent Value-An amount of money today,or the current value of a future cash flowFuture Value-An amount of money at some future time periodPeriod-A length of time(often a year,but can be a month,week,day,hour,etc.)Interest Rate-The compensation paid to a lender(or saver)for the use of funds expressed as a percentage for a period(normally expressed as an annual rate)AbbreviationsPV-Present valueFV-Future valuePmt-Per period payment amountN-Either the total number of cash flows or the number of a specific periodi-The interest rate per periodTimelines012345PVFVTodayvA timeline is a graphical device used to clarify the timing of the cash flows for an investmentvEach tick represents one time periodCalculating the Future ValueSuppose that you have an extra$100 today that you wish to invest for one year.If you can earn 10%per year on your investment,how much will you have in one year?012345-100?Calculating the Future Value(cont.)Suppose that at the end of year 1 you decide to extend the investment for a second year.How much will you have accumulated at the end of year 2?012345-110?Generalizing the Future ValueRecognizing the pattern that is developing,we can generalize the future value calculations as follows:vIf you extended the investment for a third year,you would have:Compound InterestNote from the example that the future value is increasing at an increasing rateIn other words,the amount of interest earned each year is increasingYear 1:$10Year 2:$11Year 3:$12.10The reason for the increase is that each year you are earning interest on the interest that was earned in previous years in addition to the interest on the original principle amountCompound Interest GraphicallyThe Magic of CompoundingOn Nov.25,1626 Peter Minuit,a Dutchman,reportedly purchased Manhattan from the Indians for$24 worth of beads and other trinkets(珠子和其他饰品).Was this a good deal for the Indians?This happened about 371 years ago,so if they could earn 5%per year they would now(in 1997)have:vIf they could have earned 10%per year,they would now have:Thats about 54,563 Trillion(万亿)dollars!The Magic of Compounding(cont.)The Wall Street Journal(17 Jan.92)says that all of New York city real estate is worth about$324 billion.Of this amount,Manhattan is about 30%,which is$97.2 billionAt 10%,this is$54,562 trillion!Our U.S.GNP is only around$6 trillion per year.So this amount represents about 9,094 years worth of the total economic output of the USA!.Calculating the Present ValueSo far,we have seen how to calculate the future value of an investmentBut we can turn this around to find the amount that needs to be invested to achieve some desired future value:Present Value:An ExampleSuppose that your five-year old daughter has just announced her desire to attend college.After some research,you determine that you will need about$100,000 on her 18th birthday to pay for four years of college.If you can earn 8%per year on your investments,how much do you need to invest today to achieve your goal?AnnuitiesAn annuity is a series of nominally equal payments equally spaced in time(等时间间隔)Annuities are very common:RentMortgage paymentsCar paymentPension incomeThe timeline shows an example of a 5-year,$100 annuity012345100100100100100The Principle of Value AdditivityHow do we find the value(PV or FV)of an annuity?First,you must understand the principle of value additivity:The value of any stream of cash flows is equal to the sum of the values of the componentsIn other words,if we can move the cash flows to the same time period we can simply add them all together to get the total value价值相加Present Value of an AnnuityWe can use the principle of value additivity to find the present value of an annuity,by simply summing the present values of each of the components:Present Value of an Annuity(cont.)Using the example,and assuming a discount rate of 10%per year,we find that the present value is:01234510010010010010062.0968.3075.1382.6490.91379.08Present Value of an Annuity(cont.)Actually,there is no need to take the present value of each cash flow separatelyWe can use a closed-form of the PVA equation instead:Present Value of an Annuity(cont.)We can use this equation to find the present value of our example annuity as follows:vThis equation works for all regular annuities,regardless of the number of paymentsThe Future Value of an AnnuityWe can also use the principle of value additivity to find the future value of an annuity,by simply summing the future values of each of the components:The Future Value of an Annuity(cont.)Using the example,and assuming a discount rate of 10%per year,we find that the future value is:100100100100100012345146.41133.10121.00110.00=610.51at year 5The Future Value of an Annuity(cont.)Just as we did for the PVA equation,we could instead use a closed-form of the FVA equation:vThis equation works for all regular annuities,regardless of the number of paymentsThe Future Value of an Annuity(cont.)We can use this equation to find the future value of the example annuity:Annuities Due预付年金预付年金Thus far,the annuities that we have looked at begin their payments at the end of period 1;these are referred to as regular annuitiesA annuity due is the same as a regular annuity,except that its cash flows occur at the beginning of the period rather than at the end0123451001001001001001001001001001005-period Annuity Due5-period Regular AnnuityPresent Value of an Annuity DueWe can find the present value of an annuity due in the same way as we did for a regular annuity,with one exceptionNote from the timeline that,if we ignore the first cash flow,the annuity due looks just like a four-period regular annuity Therefore,we can value an annuity due with:Present Value of an Annuity Due(cont.)Therefore,the present value of our example annuity due is:vNote that this is higher than the PV of the,otherwise equivalent,regular annuityFuture Value of an Annuity DueTo calculate the FV of an annuity due,we can treat it as regular annuity,and then take it one more period forward:012345PmtPmtPmtPmtPmtFuture Value of an Annuity Due(cont.)The future value of our example annuity is:vNote that this is higher than the future value of the,otherwise equivalent,regular annuityDeferred Annuities递延年金递延年金A deferred annuity is the same as any other annuity,except that its payments do not begin until some later periodThe timeline shows a five-period deferred annuity01234510010010010010067PV of a Deferred AnnuityWe can find the present value of a deferred annuity in the same way as any other annuity,with an extra step requiredBefore we can do this however,there is an important rule to understand:When using the PVA equation,the resulting PV is always one period before the first payment occursPV of a Deferred Annuity(cont.)To find the PV of a deferred annuity,we first find use the PVA equation,and then discount that result back to period 0Here we are using a 10%discount rate0123450010010010010010067PV2=379.08PV0=313.29PV of a Deferred Annuity(cont.)Step 1:Step 2:FV of a Deferred AnnuityThe future value of a deferred annuity is calculated in exactly the same way as any other annuityThere are no extra steps at allUneven Cash FlowsVery often an investment offers a stream of cash flows which are not either a lump sum or an annuityWe can find the present or future value of such a stream by using the principle of value additivityUneven Cash Flows:An Example(1)Assume that an investment offers the following cash flows.If your required return is 7%,what is the maximum price that you would pay for this investment?012345100200300Uneven Cash Flows:An Example(2)Suppose that you were to deposit the following amounts in an account paying 5%per year.What would the balance of the account be at the end of the third year?012345300500700Non-annual CompoundingSo far we have assumed that the time period is equal to a yearHowever,there is no reason that a time period cant be any other length of timeWe could assume that interest is earned semi-annually,quarterly,monthly,daily,or any other length of timeThe only change that must be made is to make sure that the rate of interest is adjusted to the period lengthNon-annual Compounding(cont.)Suppose that you have$1,000 available for investment.After investigating the local banks,you have compiled the following table for comparison.In which bank should you deposit your funds?Non-annual Compounding(cont.)To solve this problem,you need to determine which bank will pay you the most interestIn other words,at which bank will you have the highest future value?To find out,lets change our basic FV equation slightly:In this version of the equation m is the number of compounding periods per yearNon-annual Compounding(cont.)We can find the FV for each bank as follows:First National Bank:Second National Bank:Third National Bank:Obviously,you should choose the Third National BankContinuous CompoundingThere is no reason why we need to stop increasing the compounding frequency at dailyWe could compound every hour,minute,or second We can also compound every instant(i.e.,continuously):vHere,F is the future value,P is the present value,r is the annual rate of interest,t is the total number of years,and e is a constant equal to about 2.718Continuous Compounding(cont.)Suppose that the Fourth National Bank is offering to pay 10%per year compounded continuously.What is the future value of your$1,000 investment?vThis is even better than daily compoundingvThe basic rule of compounding is:The more frequently interest is compounded,the higher the future valueContinuous Compounding(cont.)Suppose that the Fourth National Bank is offering to pay 10%per year compounded continuously.If you plan to leave the money in the account for 5 years,what is the future value of your$1,000 investment?