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1answer
35 views

Merton portfolio allocation problem proportions/weights >1 or <0?

In the classical Merton portfolio problem, lets assume: $$ dX_t \, = \, \frac{\pi_t X_t}{S_t} S_t(\mu dt +\sigma dW_t) = \pi_t X_t (\mu dt +\sigma dW_t) $$ ie: zero interest rates for simplicity. ...
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4answers
152 views

Merton model riskless self-financing derivation

Suppose $dA_t = A_t[\mu dt+\sigma dW_t]$ (assets' value) under the physical measure, plus the other assumptions of the Merton model. Suppose further that debt and equity are tradeable assets that ...
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0answers
57 views

Calibration of Merton's jump diffusion model

Setting In my financial engineering project I'm working on a new calibration formalism for jump-diffusion models and in particular Merton's jump diffusion model. A jump diffusion process $\{X(t), t \...
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0answers
106 views

Numerical Methods for Merton Model

The stochastic differential equation for an underlying with jumps in Merton model is: $$d{{S}_{t}}=\mu \,{{S}_{t}}dt+\sigma \,{{S}_{t}}\,d{{W}_{t}}^{P}+(J-1){{S}_{t}}d{{q}_{t}}$$ where $t \quad\,\,\, ...
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0answers
48 views

The Merton's model

According to Merton's model we can calculate probability of default by this formula: $$P(V_T < B) = N \big[ \frac{\ln\frac{B}{V_0} - (\mu-\frac{1}{2}\cdot\sigma^2)T}{\sigma\sqrt{T}} \big]$$ I have ...
3
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1answer
87 views

How to find volatility of Asset given volatility of Stock in Merton model?

I encounter a problem in one of my project to find the 1 year, 2 year and 3 year Asset volatility. We are given 2015 Bell Canada's financial report and a software to do this. The financial report can ...
3
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1answer
200 views

Simple question on jump-diffusion

In the textbook by Shreve in sec. 11.7.2 a jump-diffusion process is introduced. More precisely $$ dS_t = \alpha\,S_t\,dt+\sigma\,S_t\,dW_t+S_{t-}\,d\left(Q_t-\beta\,\lambda\,t\right)\quad (1) $$ ...
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0answers
16 views

Why use Moody's KMV EDF for one year

If I were to use Moody's KMV proprietary database with expected default frequqncies(EDF) for sectors and countries, along with aggregations for financials and non-financials, significant banks etc: ...
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2answers
338 views

Solution of Merton's Jump-Diffusion SDE

In many textbooks and also in the original Merton's paper the solution of the SDE $$ dS_t = S_t\,\mu\,dt+S_t\,\sigma\,dW_t+S_{t^-}\,d\left(\sum_{j=1}^{N_t}V_j-1\right) $$ is written as $$ S_t = ...
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0answers
40 views

Future value of the debt under Merton model

The author Malz states the future value of the firm's debt under the Merton model can be found from: $$ D_{t} = D - \max(D - A_{t} , 0) $$ (where $D$ is the par value of the debt, $A_{t}$ is the ...
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2answers
368 views

Why is the value of debt modeled as a short put option in Merton's model?

Can someone give me an intuitive understanding of why the Merton model models the value of the debt from the lender's point of view as a short put with a risk free bond? I'm not well versed in this ...
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0answers
50 views

Merton Jump Diffusion Model: Influence of lambda

I use Monte Carlo to simulate sample paths of Merton's jump diffusin model. By plotting a histogram of the log returns and using kerneldensity to approximate the density function I try to look at the ...
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1answer
122 views

Question about the stochastic differential equation in the Merton model

in the following stochastic differential equation merton model we have $$\frac{ds}{s}=(\alpha-\lambda k)dt+\sigma dW+dq$$ where $\alpha$ is the instantaneous expected return on the stock; $\sigma^2$...
3
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1answer
235 views

How to interpret negative asset volatility numerical results in Merton model?

I am currently working on my thesis where I discuss the Merton default probability model. I have a huge sample of US firms for the period 1990-2010. I use both numerical and complex iterative approach ...
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0answers
241 views

How to calculate modeled asset volatility by industry factor?

Currently I am working with huge data frame which consists of a lot firms. For each firm in my sample I calculated asset volatility ( I am using Merton default probability model, so I have used 2 ...
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2answers
3k views

How to use Merton model to calculate default probability with monthly stock prices?

I want to calculate the estimated default probability with only given data the monthly returns for the last 20 years, the risk-free rate ($R_f$), equity value (EV) and the face value of debt ($D$). My ...