Chapter 3: Time Value Of Money
Time Value of Money
Concept:
Money now is more valuable than money later.
Reason:
Money can be used to generate more money.
Ways to Generate Money:
Running a business.
Buying and selling items for a profit.
Saving money in a bank to earn interest.
Compound Interest
Definition:
Compound interest is the interest paid on interest, or the reinvestment of interest paid on an investment’s principal.
Principal: The face value of the deposit or debt instrument.
How Does it Work?
Example: Compound Interest at 6% Over Time
Initial Investment: $100 (Present Value, PV)
Interest Rate: 6% (denoted as 'i')
First Year:
Future Value (FV) after 1 year = $100 + ($100 * 0.06) = $106.
After 10 Years:
Future Value = $179.08.
Total interest earned = $79.08.
Reference: Keown/Personal Finance, 9th Ed - CH 3 Figure 3.3
Savings Calculation Utilizing a Calculator
Scenario: Using Calculator.net for Compound Interest at 6%
Initial Investment: $100 (PV)
First Year: FV = $106.
After 10 Years:
Future Value = $179.08, earning $79.08 interest.
Compound Interest with Additional Payments
Periodic Deposits at End of Compound Period:
Strategy: Deposit an additional $100 annually for 10 years
Total Amount After 10 Years:
Future Value = $1,497.16
Total interest earned = $397.16.
Periodic Deposits at Beginning of Compound Period:
Strategy: Same additional deposits
Total Amount After 10 Years:
Future Value = $1,497.16
Total interest earned = $476.25.
Conclusion: Deposits made earlier yield higher interest payouts.
Future Value Calculation
Example Calculation with 10% Interest:
Present Value: $1,000
Calculation:
$1,000 x 0.10 = $100 (first year interest)
Balance after 1 year = $1,000 + $100 = $1,100 (FV)
Growth Over Years:
Year 2: $1,100 x 1.10 = $1,210
Year 3: $1,210 x 1.10 = $1,331
Year 4: $1,331 x 1.10 = $1,464.10
Year 5: $1,464.10 x 1.10 = $1,610.51
Formula:
Future Value = Present Value x (1 + r)^n
$1,000 x (1.10)^5 = $1,610.51
Formulas
Future Value Formula:
Using letters:
FV = PV x (1 + r)^n
Where:
PV = Present Value
r = Interest Rate
n = Number of Periods
Present Value Formula:
Using letters:
PV = FV ÷ (1 + r)^n
Where:
FV = Future Value
r = Interest Rate
n = Number of Periods
Present Value vs Future Value
Present Value:
Answers the question: What is it worth in today's dollars?
Future Value:
Answers the question: If I invest X amount today at a certain interest rate, how much will I have in the future?
The Power of Time in Compounding
Scenario:
Selma and Patty saving for retirement over 35 years.
Selma invests $2,000 annually for 10 years.
Patty waits 10 years to start investing the same amount.
Long Term Compounding Examples
Investment of $2,400:
One-time deposit at varying annual interest rates, adding another $2,400 yearly:
0.42% for 40 years
1% for 40 years
5% for 40 years
Present Value Requirement for Retirement
Objective: Need $5,000,000 in 40 Years
At 5%:
Required investment = $710,228.41
At 10%:
Required investment = $110,474.64
Significance:
Emphasizes the importance of early investment.
The Rule of 72
Purpose: Estimate doubling time of an investment.
Formula:
Years to double = 72 ÷ interest rate
Example:
9% annual growth = 72 ÷ 9 = 8 years to double.
Importance of Interest Rates
Interest rate is crucial in determining how much an investment grows.
Quote:
“Compound interest is the eighth wonder of the world.” - Warren Buffet.
Daily Compounding Examples
1¢ at 100% Compounded Daily:
Day 1: $0.01
Day 2: $0.02
Day 3: $0.04
Day 4: $0.08
Progression:
5 days: $0.16
6 days: $0.32
31 days: $10,737,418.24, demonstrating the power of compounding.
Questions and Additional Resources
Available on Canvas:
Hypothetical Savings Plan
Article: "No Matter How Old You Are, You Can Retire with $1M"