Cash Flow Additivity
Learning Outcome Statement:
Explain the cash flow additivity principle, its importance for the no-arbitrage condition, and its use in calculating implied forward interest rates, forward exchange rates, and option values.
Summary:
The cash flow additivity principle states that the present value of any future cash flow stream indexed at the same point equals the sum of the present values of the cash flows. This principle is crucial in ensuring that market prices reflect the condition of no arbitrage, meaning there's no possibility to earn a riskless profit in the absence of transaction costs. It is applied in various financial calculations including implied forward interest rates, forward exchange rates, and option pricing.
Key Concepts:
Cash Flow Additivity
The principle that the present value of a series of future cash flows, when indexed at the same point, equals the sum of the present values of individual cash flows. This ensures consistency in valuation and prevents arbitrage opportunities.
Implied Forward Rates
Forward rates calculated under the assumption of no arbitrage using cash flow additivity. These rates ensure that two investment strategies with the same cash flows have the same present value, thus preventing arbitrage.
Forward Exchange Rates
Exchange rates set today for currency exchanges that will occur at a future date, calculated to prevent arbitrage opportunities by ensuring that investment in different currencies but with similar risk profiles will yield the same return.
Option Pricing
The process of determining the fair value of options using models like the binomial model, where the cash flow additivity principle helps ensure that the option price reflects the possibility of different future states without allowing for arbitrage.
Formulas:
Implied Forward Rate
This formula calculates the implied one-year forward rate starting in one year, ensuring no arbitrage between investing for two years and investing for one year then reinvesting for another year.
Variables:
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- One-year forward rate starting in one year
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- One-year spot rate
- :
- Two-year spot rate
Present Value of Cash Flows
This formula calculates the present value of a series of future cash flows, discounted back to the present time, applying the principle of cash flow additivity.
Variables:
- :
- Present value of the cash flows
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- Cash flow at time t
- :
- Discount rate
- :
- Time period
- :
- Total number of periods