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ECON 251: Financial Theory

Lecture 14 - Quantifying Uncertainty and Risk. Until now, the models we've used in this course have focused on the case where everyone can perfectly forecast future economic conditions. Clearly, to understand financial markets, we have to incorporate uncertainty into these models. The first half of this lecture continues reviewing the key statistical concepts that we'll need to be able to think seriously about uncertainty, including expectation, variance, and covariance. We apply these concepts to show how diversification can reduce risk exposure. Next we show how expectations can be iterated through time to rapidly compute conditional expectations: if you think the Yankees have a 60% chance of winning any game against the Dodgers, what are the odds the Yankees will win a seven game series once they are up 2 games to 1? Finally we allow the interest rate, the most important variable in the economy according to Irving Fisher, to be uncertain. We ask whether interest rate uncertainty tends to make a dollar in the distant future more valuable or less valuable. (from oyc.yale.edu)

Lecture 14 - Quantifying Uncertainty and Risk

Time Lecture Chapters
[00:00:00] 1. Expectation, Variance, and Covariance
[00:19:06] 2. Diversification and Risk Exposure
[00:33:54] 3. Conditional Expectation
[00:53:39] 4. Uncertainty in Interest Rates

References
Lecture 14 - Quantifying Uncertainty and Risk
Instructor: Professor John Geanakoplos. Transcript [html]. Audio [mp3]. Download Video [mov].

Go to the Course Home or watch other lectures:

Lecture 01 - Why Finance?
Lecture 02 - Utilities, Endowments, and Equilibrium
Lecture 03 - Computing Equilibrium
Lecture 04 - Efficiency, Assets, and Time
Lecture 05 - Present Value Prices and the Real Rate of Interest
Lecture 06 - Irving Fisher's Impatience Theory of Interest
Lecture 07 - Shakespeare's Merchant of Venice and Collateral, Present Value and the Vocabulary of Finance
Lecture 08 - How a Long-Lived Institution Figures an Annual Budget; Yield
Lecture 09 - Yield Curve Arbitrage
Lecture 10 - Dynamic Present Value
Lecture 11 - Social Security
Lecture 12 - Overlapping Generations Models of the Economy
Lecture 13 - Demography and Asset Pricing: Will the Stock Market Decline when the Baby Boomers Retire?
Lecture 14 - Quantifying Uncertainty and Risk
Lecture 15 - Uncertainty and the Rational Expectations Hypothesis
Lecture 16 - Backward Induction and Optimal Stopping Times
Lecture 17 - Callable Bonds and the Mortgage Prepayment Option
Lecture 18 - Modeling Mortgage Prepayments and Valuing Mortgages
Lecture 19 - History of the Mortgage Market: A Personal Narrative
Lecture 20 - Dynamic Hedging
Lecture 21 - Dynamic Hedging and Average Life
Lecture 22 - Risk Aversion and the Capital Asset Pricing Theorem
Lecture 23 - The Mutual Fund Theorem and Covariance Pricing Theorems
Lecture 24 - Risk, Return, and Social Security
Lecture 25 - The Leverage Cycle and the Subprime Mortgage Crisis
Lecture 26 - The Leverage Cycle and Crashes