1. Functionality of Banks and Hedge Funds and Contagion Between Financial Institutions: A System Dynamics Approach Wednesday, March 13 Mila Getmansky Andrew W. Lo

2. Intro to System Dynamics Example: Cobweb Model: Solution: Behavior: Oscillation with a period equal to twice the interval between time periods

3. Extensions Do not represent stock and flow structure of real markets (inventories, work in process, and production capacity) Formulated in discrete time The interval between periods is assumed to correspond to the time required to produce the commodity. However, the observed periods of commodity cycles are much greater than twice the production delays. (The construction time for commercial buildings is about 3 years, but the real estate cycle ranges from 10 to 20 years).

4. Extensions The model does not distinguish between production capacity and capacity utilization and so cannot explain the multiple oscillatory periods observed in many industries. Behavioral decision processes of the market are not modeled.

5. Corporate Growth Model Explain differences in: –Growth patterns –Stability –Market share –Profitability Different patterns found: –Within the same industry –Occurring in same time frame Not explained by: –Product –Quality

6. Model Size –60 Levels (Integrations) –250 Variables Top management power structure –90% intangible variables Connect major sectors Goals and traditions are the basis for decisions Information channels (between market and company)

7. SD Versus Traditional Approach Not an equilibrium model (unless at steady- state); Focus is Dynamics Objective: understand dynamics of underlying structure of a system such as hedge fund, contagion, etc.; model the impact of different scenarios and decisions versus finding an optimal point estimate

8. Reinforcing Loops Loops with all positive (or an even number of negative) links are reinforcing feedback loops. Reinforcing loops create exponential growth or decline. They give a system inertia. Time Bank balance

9. Balancing Loops Balancing loops are created when there are an odd number of negative links. Balancing loops move the system towards a goal. They give a system stability. Time Demand Supply

10. Stock and Flow Diagrams Stocks represent accumulations and are generally measured in units (dollars) Flows change the level of stocks and are usually measured in units per time (dollars/month)

11. Hedge Funds – An Overview What are hedge funds? –Unregulated investment partnerships available to wealthy individuals and institutions (“sophisticated accredited investors”) –Seek above-average returns using aggressive, high-risk strategies unavailable to mutual funds and other traditional money managers

12. More on Hedge Funds Investing strategies include, but are not limited, to: –Short selling –Leverage –Arbitrage –Derivatives Compensation structure is as follows: –Percentage of assets under management (usually 1%) –Percentage of profits (usually 20%)

13. Why Are Hedge Funds Interesting? Due to their unregulated nature, hedge funds can take on huge positions, affect market dynamics and cause financial collapses: –LTCM in the 1997 Asian crisis and the 1998 Russian debt crisis ($3.6 billion bailout plan to rescue the fund) –Soros in the 1992 ERM crisis (funded a $10 billion short position in sterling, using collateral and margins) Understanding the role of hedge funds in the global financial markets might help prevent future crises

14. Types of Hedge Funds Major investment styles are the following: –Macro funds –Global funds –Long only funds –Market-neutral funds –Sectoral hedge funds –Dedicated short sales funds –Event-driven funds –Funds of funds

15. More Types of Hedge Funds Additional categories of hedge funds include: –Special situation funds –Pure equity funds –Convertible arbitrage funds –Commodity trading advisor funds –Private equity funds –Risk arbitrage funds –Emerging market funds –Restructured or defaulted security funds

16. Objective of Paper Understand the conditions under which a financial institution (hedge fund or bank) can fail Determine when the collapse of such an institution can trigger a contagion effect that leads to the failure of another institution

17. Functional Diagram of a Hedge Fund

18. Functional Diagram of a Bank

19. General Accounting Framework Assets = Liabilities + Equity AssetsLiabilities -Cash -Total investments -Loans Equity

20. Modeling Variables CASH INVESTMENTS –Low risk –Medium risk –High risk LOANS –Short-term –Long-term LIABILITIES –Deposits –Interest owed to depositors EQUITY –Capital gains –Interest payments –Interest owed to depositors –Defaults

21. Generic Accounting Framework

22. Flows: Bank Lends to a Hedge Fund Bank lends money to a hedge fund. It earns interest. Hedge fund borrows money from a bank. It has to pay interest.

23. Flows: Bank Invests in a Hedge Fund Bank invests in a hedge fund. It earns returns. Hedge fund receives money from the bank and usually invests right away.

24. Ways a Bank Can Fail, Equity<0, Reserve Ratio<Required RR No capital gains (capital losses) –Bank does not make prudent decisions in risky investments –Market collapses –Hedge fund makes poor investments Defaults on principal –Hedge fund or another borrower defaults on loans Defaults on interest payments

25. Ways a Hedge Fund Can Fail, Equity<0 Makes poor investment decisions General market conditions are weak Investors exiting Banks or other lending institutions decide not to lend (make new deposits), especially in crises times when liquidity is very much needed

26. Decision Points That Can Potentially Lead to Crises and Contagion Effects Presence of a rogue trader Hedge fund style of investment Effect of leverage on: –Reputation –Deposits/Withdrawals –Lending

27. Cost and Risk of Leverage

28. Return Potential

29. Reputation

30. Rogue Trader Losses Bets Probability of a rogue trader Skill

31. Behavior of Rogue Trader

32. Summary and Conclusions Dynamics Are Critical Effects Are Highly Nonlinear Implications for: –Credit –Liquidity –Volatility –Regulatory Environment