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"