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Financial Economics - Exam 2005 - Statistics and Economics, Exams of Economic statistics

Professor Malcolm Brown, University of Kent, Statistics and Economics, Financial Economics, Exam 2005, FACULTY OF SCIENCE, TECHNOLOGY AND MEDICAL STUDIES, Efficient Markets Hypothesis, informational inefficiency, Variance of return, Semi-variance of return, Shortfall probability, Expected shortfall, optimal portfolio, Wilkie stochastic investment model, standard Brownian Motion, previsible process, standard Black Scholes formula.

Typology: Exams

2010/2011

Uploaded on 10/04/2011

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UNIVERSITY OF KENT
FACULTY OF SCIENCE, TECHNOLOGY AND MEDICAL STUDIES
LEVEL H EXAMINATION
GRADUATE DIPLOMA IN ACTUARIAL SCIENCE
GRADUATE CERTIFICATE IN ACTUARIAL SCIENCE
FINANCIAL ECONOMICS
Friday, 13 May 2005 : 9.30 – 12.30
This paper contains NINE questions. Answer ALL questions.
The marks allocated are shown at the end of each question.
Copies of Formulae and Tables for Actuarial Examinations are provided.
Approved calculators may be used.
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UNIVERSITY OF KENT

FACULTY OF SCIENCE, TECHNOLOGY AND MEDICAL STUDIES

LEVEL H EXAMINATION

GRADUATE DIPLOMA IN ACTUARIAL SCIENCE

GRADUATE CERTIFICATE IN ACTUARIAL SCIENCE

FINANCIAL ECONOMICS

Friday, 13 May 2005 : 9.30 – 12.

This paper contains NINE questions. Answer ALL questions. The marks allocated are shown at the end of each question.

Copies of Formulae and Tables for Actuarial Examinations are provided. Approved calculators may be used.

  1. (a) Describe informational efficiency in the context of the Efficient Markets Hypothesis. [4 marks]

(b) Briefly outline five examples of effects that have been claimed to exist in stock markets that might be considered examples of informational inefficiency. [5 marks]

(c) List the reasons, with brief explanations, why it is difficult to assess empirically whether or not the market is efficient. [4 marks] [Total: 13 marks]

  1. Define the following measures of investment risk along with all terms you use in your definition:

(a) Variance of return

(b) Semi-variance of return

(c) Shortfall probability

(d) Expected shortfall [Total: 6 marks]

  1. (a) Explain the following terms in the context of mean-variance portfolio theory, being careful to state any assumptions needed:

(i) opportunity set (ii) efficient frontier for a portfolio of risky assets (iii) indifference curves (iv) optimal portfolio [7 marks]

(b) In the city state of Metaphoria, there are two assets (Asset A and Asset B ) available to investors. There are four possible (non-independent) investment outcomes over the investment period, as follows:

Outcome Return on Asset A (RA)

Return on Asset B (RB)

Probability

6. (a) State the five properties for a stochastic process { B t ( ) : t ≥ 0 }to be defined as

standard Brownian Motion. [3 marks]

(b) Let { B t ( ) : t ≥ 0 }be a standard Brownian motion and define:

B t tB t

for t > 0 , with B 1 ( 0 )= 0

(i) Calculate the mean and variance of B 1 ( t )and the covariance of B 1 ( s )

and B 1 ( t )where s < t.

(ii) Hence deduce that B 1 ( t )is a standard Brownian motion and thus has

the same distributional properties as B t ( ).

(iii) Show that the two probabilities:

P  B t ( )< ct  for all t ≥ 1

and P  B t ( )< c  for all 0 ≤ t ≤ 1

are equal to one another where c > 0 is a constant. [8 marks]

(c) You are given the probability density function of 1 ( )

0 1 max t M B t ≤ ≤ = is:

fM 1 ( t )= 2 ( ) φ t for t ≥ 0

fM 1 ( t )= 0 for t < 0

where φ is the density function of a standard normal random variable. Find

an expression in terms of c for the probabilities in part b) (iii). [3 marks] [Total: 14 marks]

  1. (a) Define the following:

(i) a European call option (ii) an American put option [2 marks]

(b) Suppose that there are three European call options on a non-dividend paying share with the same exercise date. The exercise prices of the three options are X (^) 1 , X 2 & X 3 (with X (^) 1 < X 2 < X 3 & X 3 − X 2 = X 2 − X 1 ).

(i) An investor purchases one call option with exercise price X 1 and one call option with exercise price X (^) 3. The share price at the exercise date is equal to S with S > X 3. Determine how many call options with exercise price X (^) 2 the investor will need to purchase or sell at the same time in order to obtain a payoff that is independent of S.

(ii) Show that the portfolio developed in b)(i) above provides a non-negative payoff for all possible values of S ≥ 0.

(ii) The current values of the options are c 1 (^) , c 2 & c 3 respectively. Develop an upper bound for c 2 in terms of c 1 and c 3. [8 marks] [Total: 10 marks]

  1. The price of a non-dividend paying share over each one-month period t -1 to t either increases by a factor ut − 1 ( j ) or decreases by a factor dt − 1 ( j )where j denotes the state at time t -1. The states are labelled such that from each state j the process can move up to state 2 j -1 or down to state 2 j. The continuously compounded risk-free rate of interest is r.

(a) Calculate from first principles the equivalent measure Q (i.e. each qt ( j )) such that the discounted share price Dt = ertSt is a martingale. [3 marks]

(b) Let cT be the payoff from a European call option on the share that has an exercise price K and exercise time T. Show that E (^) t = erTEQ [ cT | Ft ]is also a martingale. [2 marks]

(c) Let 1

1 −

− −

t t

t t t D D

E E

(i) Define what is meant by a previsible process.

(ii) By considering the possible values that φ t can take, show that φ t is

previsible without using the martingale representation theorem. [9 marks] [Total: 14 marks]

  1. (a) A non-dividend paying stock has a current price of 100p and a volatility of 25% per annum. The continuously compounded risk-free rate is 5% per annum.

Using the standard Black Scholes formula, calculate the price of

(i) a one year European call option with an exercise price of 110p (ii) a one year European put option with an exercise price of 110p [6 marks] (b) Explain in general terms why the prices actually quoted in the market may differ from the theoretical Black-Scholes price. [2 marks]

(c) Calculate the volatility to within 1% p.a. implied by a call option price of 10p. [4 marks] [Total: 12 marks]