Questions tagged [math]
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Evaluating contract $D$ where the stock follows the Black Scholes assumption
Ch.7 Mark Joshi Problem 14
A contract, $D$, pays $30\%$ of the increase (if any) of a stock's value in a year. If $S_t$ follows Black-Scholes assumptions, give a formula in terms of the Black-...
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1answer
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Properties of Brownian motion and filtration, Exercise 6.22, Joshi Concepts and applications to mathematical finance
Let $W_t$ be a Brownian motion, and let $F_t$ be its filtration then for $t > s$ we are asked to compute
$$\mathbb{E}\left[W_t^2|F_s\right]$$
We have $$W_t = W_s + (W_t - W_s)$$
and
$$W_t^{2} ...
3
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1answer
104 views
Mark Joshi, The concepts and practice of mathematical finance chapter 6 exercise 20,21
Find the Black-Scholes price of an option paying
$$(S_T^{\alpha} - K)_{+}$$ at time $T$.
Solution - The forward price is given by
$$F_T(t) = e^{r(T-t)}S_t$$
So,
$$F_T(0) = e^{rT}S_0$$
and
$...
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1answer
149 views
Joshi, Exercise 2.7 Concepts of Mathematical Finance
Let $D(K)$ pay $(S - K)^2$ if $S > K$, zero otherwise. Show that if $D(K)$ is differentiable function of $K$ then the third derivative w.r.t $K$ is non-negative.
From what the hint in the book, we ...
1
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0answers
69 views
Moving average variance [closed]
I have generated a random series of returns drawn from a normal distribution and generated a random price series by compounding these returns (X) so $P_i = P_1(1+X)^i$. I want to show the analytic ...
1
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0answers
150 views
What jobs in Finance are most math intensive? [closed]
I'm a math major and I've always been really interested in Finance; however, I'm starting to enjoy math more and more and would like to know which jobs in Finance use the most/more advanced math. Also,...
2
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1answer
610 views
Given two risky stocks calculate the rate of return, standard deviation, beta, and risk-free rate
Consider a world where there are only two risky stocks, $A$ and $B$, whose details are listed in the table below:
Furthermore, the correlation between the returns of stocks $A$ and $B$ is $\rho_{A ...
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1answer
146 views
Using CAPM to derive the following
Background Information:
Say there are $s = 1,\ldots,S$ possible future outcomes (states) with known probabilities $\pi_s > 0$, $\sum_{s=1}^{S}\pi_s = 1$. Define the expected payoff as $\mathbb{E}_\...
-1
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2answers
95 views
Given three stocks what is the fraction of each stock's risk is diversified away
Consider an equally weighted portfolio of three stocks, each of which
is independently distributed of the others but have the same risk. I.e.,
$cov(r_i, r_j) = 0$; $\forall i \neq j$, and $\...
-2
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1answer
217 views
How to solve $dX_t = X_t(\sigma_t dW_t + \mu_t dt)$?
Solve the SDE $$dX_t = X_t(\sigma_t dW_t + \mu_t dt)$$ where $\sigma_t$,$\mu_t$ are deterministic.
Attempted solution
We have $$dX_t = X_t(\sigma_t dW_t + \mu_t dt)$$
Let $f(x) = \log X$, applying ...
0
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1answer
36 views
Price of every asset in discrete market model strictly increasing
If the price of every asset in a discrete model is strictly increasing, with probability one, then does the market admit arbitrage?
Thoughts: I believe this is true but I am not sure how to give an ...
1
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1answer
58 views
Implied Expected Stock Return from European Option Prices
We can calculate the expected stock return (under the measure $Q$) from at-the-money ($K=S_t$) option prices as:
$$E\left(\frac{S_T-S_t}{S_t}\right)=\frac{e^{rT}}{S_t}(C_t-P_t)$$
The result is ...
