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Personal Finance - Money and the Time Value of Money
Overview Really, though everything in business is focused on one thing – money. In this lesson we will look at what money is and what functions it performs in society. We will also look at some basic banking functions, primarily how “interest” is calculated so next time you finance a car or home you will have an understanding of the process. MONEY History What IS money? The Island of Stone Money -- From Money Mischief by Milton Friedman. The island of Yap in Micronesia is a German colony, with a local population of about five or six thousand natives and a handful of German administrators. The island yields no metal, so the local population has taken recourse to stone as a medium of exchange. They call this currency “fei”, and it consists of large, solid, thick, stone wheels, ranging in diameter from a foot to twelve feet, having in the center a hole varying in size with the diameter of the stone, wherein a pole may be inserted sufficiently large and strong to bear the weight and facilitate transportation. These stone “coins” were made from limestone found on an island some four hundred miles distant. They were originally quarried and shaped on that island and the product brought to Yap by some venturesome native navigators, in canoes and on rafts. A noteworthy feature of this stone currency is that it is not necessary for its owner to reduce it to possession. After concluding a bargain which involves the price of a fei too large to be conveniently moved, its new owner is quite content to accept the bare acknowledgement of ownership and without so much as a mark to indicate the exchange, the coin remains undisturbed on the former owners premises. My faithful old friend, Fatumak, assured me that there was in the village near by a family whose wealth was unquestioned, and yet no one, not even the family itself, had ever laid eye or hand on this wealth. It consisted of an enormous fei, whereof the size is known only by tradition; for the past two or three generations it had been, and at that very time it was lying at the bottom of the sea! Many years ago an ancestor of this family, on an expedition after fei, secured this remarkably large and exceedingly valuable stone, which was placed on a raft to be towed homeward. A violent storm arose, and the party, to save their lives, were obliged to cut the raft adrift, and the stone sank out of sight. When they reached home, they all testified that the fei was of magnificent proportions and of extraordinary quality, and that it was lost through no fault of the owner. Thereupon it was universally conceded in their simple faith that the mere accident of its loss overboard was too trifling to mention, and that a few hundred feet of water off shore ought not to affect its marketable value, since it was all chipped out in proper form. The purchasing power of that stone remains, therefore, as valid as if it were leaning visibly against the side of the owner’s house. So what are the characteristics of money, and how do they apply to fei?
Characteristics of Money
The Money Supply First, it is the responsibility of the US Department of the Treasury to report on the Money Supply, and they measure the supply by looking at:
The total is reported as the current value of “M1”. Banks Create Money So, when “The Fed” raises rates, the banks raise their rates to consumers, who ask for fewer loans. Fewer cashiers checks are issued, and viola!, less money in circulation. INTEREST AND THE TIME VALUE OF MONEY Interest
The first two components of the interest rate listed above, the real rate of interest and an inflation premium, collectively are referred to as the nominal risk-free rate. In the US, the nominal risk-free rate can be approximated by the rate of 13 week US Treasury bills since they are generally considered to have a very small risk. Simple Interest Simple Interest = p * i * n - where: Example: You borrow $10,000 for 3 years at 5% simple annual interest. - interest = p * i * n = 10,000 * .05 * 3 = 1,500 [$10,000 * .05 = $500 for each of three years.] Compound Interest You can think of compound interest as a series of back-to-back simple interest contracts. The interest earned in each period is added to the principal of the previous period to become the principal for the next period. For example, you borrow $10,000 for three years at 5% annual interest compounded annually: - interest year 1 = p *
i * n = 10,000 x .05 * 1 = 500 Total interest earned over the three years = 500 + 525 + 551.25 = 1,576.25. Compare this to 1,500 earned over the same number of years using simple interest. Note that in comparing growth graphs of simple and compound interest, investments with simple interest grow in a linear fashion and compound interest results in geometric growth. So with compound interest, the further in time an investment is held the more dramatic the growth becomes. Charts - Copyright© 1999-2001 studyfinance.com
THE TIME VALUE OF MONEY The “Real Rate of Interest” described above is based on the idea that a dollar received today is more valuable than a dollar to be received in the future. A dollar in hand today is worth more than a dollar to be received in the future because a dollar today can be invested so you will have more than a dollar in the future. – Rock Mathis, New Jersey Institute of Technology Suppose you were given two choices: $10,000 received today, or $12,000 received in five years time. Which would you choose? Well, to answer this you would have to know how much more money you would need in five years to have the same buying power, at that time, as the $10,000 has today. Keeping up with inflation might be your first concern. How much would the original amount have to be in order to have grown with inflation. Let’s say inflation is 3%. If we add 3% per year we will have a chart that looks like this: (Gee, this looks just like compound interest!) Year
One: $10,000 * 3% (.03) = $300 + original $10,000 = $10,300 At 3%, then, if you took the original $10,000 and it grew in value at just the inflation rate, you would have $11,593 in five years. So at an assumed rate of 3%, the $12,000 in five years offer is better than $10,000 today. This is true, however, only if you believe that 3% is the maximum growth you could expect. If you expect a 5% growth rate, the chart looks like this: Year
One: $10,000 * 5% (.05) = $500 + original $10,000 = $10,500 $10,000 would grow to $12,763, so now you would choose the $10,000 today instead of the $12,000 in five years. Now the opposite - what if we are given the choice of a payment in the future, or a lesser amount today; how do you choose? (In the lottery, winners are given a choice, $1,000,000 over 20 years, or a lump sum today – what analysis should they use to figure which one to pick?) Present Value The calculation for this will tell us the Present Value of $12,000 in five years at 3%.
x
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where PV = present Value
5 = $12,000/ (1.03 * 1.03 * 1.03 * 1.03 * 1.03) = $12,000/ 1.16 = $10,345 So given the choice of $10,000 today or $12,000 in five years, at 3% the Present Value of $12,000 is $10,345. Since we would only be getting $10,000 today, we would choose the $12,000 in five years. Now assume the same amount and length of time, except at an expected growth rate of 5%.
5 = $12,000/ (1.05 * 1.05 * 1.05 * 1.05 * 1.05) = $12,000/ 1.28 = $9,375 At 5% the $12,000 in five years has a Present Value of only $9,375. If we take the $10,000 today, we would potentially be able to have more than $12,000 in five years. (As we learned about with compound interest, we would actually have $12,763 in five years!) At 5%, take the $10,000 today. The following link goes over these concepts again from a different angle. http://www.studyfinance.com/lessons/timevalue/ |
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