Questions tagged [risk-neutral-measure]

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Prove that $d\hat{W}_t = dW_t - \frac{1}{N_t} \cdot dN_t\cdot dW_t$ gives a Brownian motion under forward measure

Let $N_t$ be a numeraire and $(W_t)$ be the standard Brownian motion under the risk-neutral probability measure $P$. Recall that forward measure $\hat{P}$ is defined as the Radon-Nikodym derivative: $...
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3answers
173 views

How can I use the Radon-Nikodym theorem to show that forward measure is indeed measure?

The following statements are taken from the Wikipedia page for forward measure. Let $$B(T)=\exp \left(\int _{0}^{T}r(u)\,du\right)$$ be the bank account or money market account numeraire and $...
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38 views

$E_p(e^{-\int_j^k r(t)dt})=B(0,j)$

Consider $r(t)$ the spot rate of default-free interest where $B(t,T)$ represents the $T$-maturity zero-coupon bond price at time $t$. Also assume, we are taking the expectation under the risk-netural ...
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1answer
85 views

Market Price of Risk for Consumption Asset - Hull's Example 28.1

In Hull's Options, Futures, and Other Derivatives, he gives an example 28.1 as below. Consider a derivative whose price is positively related to the price of oil and depends on no other ...
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251 views

Pricing call option using risk-neutral martingale approach with squared stock price boundary?

I have to use the risk-neutral martingale 5 step approach under BS pricing framework to price the following call option at time 0: $$X = \begin{cases}1, &{if} &S_T^2\geq K,\\0, & {...
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1answer
209 views

What is a Brownian motion “under the risk-neutral” measure?

I understand that the risk-neutral measure is one under which the discounted price (acc. to the risk-free rate) of any asset is a martingale. But we also see notation like $\mathbb{W}^Q_t$ to denote a ...
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1answer
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How is Radon-Nikodym derivative different from the likelihood ratio?

I see that the Radon-Nikodym derivative is the ratio of probability measures, $dP/dQ$. How is this different, in general, from a likelihood ratio of two continuous distributions? I understand the RN-...
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1answer
39 views

How do we derive the Radon-Nikodym derivative for T-forward measures?

Let $Q^{T_e}$ denote the $T_e$-forward measure and let $Q^{T_p}$ denote the $T_p$-forward measure. I have seen the following Radon-Nikodym derivative being used in derivations. For $0 \le t \le T_p$, ...
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2answers
73 views

How do we determine the “correct measure”?

Frequently I come across the statement that the "correct measure" for a product is this-or-that measure. For example, Eurodollar Futures or Stock returns - Risk neutral measure Libor forward rate - T-...
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1answer
111 views

Going from $\mathcal{P}$ to $\mathcal{Q}$

Under $\mathcal{P}$, we have the Heston Model given by: $$ d S_{t}=\mu S_{t} d t+\sqrt{\nu_{t}} S_{t} d W_{t}^{S},\\ d \nu_{t}=\kappa\left(\theta-\nu_{t}\right) d t+\xi \sqrt{\nu_{t}} d W_{t}^{\nu}. $...
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24 views

Weighting function for parametric estimation of the Risk-neutral density function

I would like to estimate the Risk-neutral density function (RND) implicit in financial Call option prices by a parametric approach where the parameters of the RND (for instance mean and variance for a ...
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36 views

Risk-neutral Simple Return Moment Log-return Moment

I am trying to find a way to link Risk-neutral moment of simple return to risk-neutral moment of log-returns. Specifically, by making the same standard assumptions of the Black-Scholes model with the ...
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Risk Neutral Density Curve for SPY Options looks very weird

I have created a risk neutral density curve using SPY weekly options and the RND package in R. I calculated the risk neutral density for the Feb07 options. The curve looks very weird when I look at ...
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Why price with lower volatility yield higher expectation under risk neutral measure

Suppose $S_1$ and $S_2$ are two asset prices, such that, E[$S_1$] = E[$S_2$] under physical measure and $\sigma(S_1)$ > $\sigma(S_2)$. Then why E[$S_1$] < E[$S_2$] under the risk neutral ...
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Risk-neutral price of $H=e^{X_T^1+X_T^3}$

Let $B=(B_t^1,B_t^2,B_t^3)$ a $\mathbb R^3$-valued Brownian motion. Let $r_t$ (risk free rate) be bounded and deterministic. Let consider the DISCOUNTED market $$d\overline X_t^1=\frac52dt+2dB_t^1-...
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1answer
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What is the connection between the risk neutral implied density and the real world density?

I understand that we can use option prices to imply volatilities and ultimately to imply a risk neutral density. I also understand that this implied density is not the same as the "real world density"....
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1answer
103 views

How To Understand the Drift of ln(S) if S Follows Geometric Brownian Motion

As we know, if an asset S follows geometric Brownian motion, under risk neutral measure, it can be expressed as $\frac{dS}{S}=rdt+\sigma dW$, by applying Ito's lemma, $d(lnS)=(r-0.5*σ^2)dt+σdW(t)$, ...
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Stochastic Volatility Models Real World Calibration

I am trying to find some research pertaining to the historical (or real world) calibration of stochastic volatility models. For example, in applications such as counterparty credit risk (IMM) or ...
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1answer
77 views

Risk Neutral Pricing and the Drift

For risk neutral pricing, why do we want to compute expectation of a martingale? why is this so important? Why do we dislike the drift so much? Avoid math heavy answers please.
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2answers
108 views

How to Understand Lognormal Distribution in the Following Case

I got a question and corresponding solution, but have some difficulties in understand the lognormal distribution part of it, so I really appreciate your advice: Question: assume zero interest rate ...
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30 views

Confirm If Risk-Neutral Measure is Unique in My Following Case

I'm reading a book that discusses about derivatives pricing and have some doubts about a particular problem and really appreciate your advice: Question: Assume a non-dividend paying stock follows a ...
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1answer
257 views

Is “risk-neutral probability” a misnomer?

Aside from not being a probability in the common sense (i. e. not concerning the odds of events), as far as I understood it, the "market's attitudes towards risk" are actually factored into / built in ...
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What's the relationship between the risk-neutral probability in HJM and the risk-neural probability under domestic money market?

In shreve's book, we model the stock price dynamics as: $$S_i(t) = \alpha(t)S_i(t)dt +S_i(t)\sum ^d_{j=1}\sigma _{ij}(t)dW_j(t)$$ and the forward rate can be written as : $$df(t,T) = \gamma(t,T)dt + \...
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220 views

Assumptions in using risk-neutral pricing formula

The well-known risk-neutral pricing formula goes as follows (extracted from Shreve's Volume 2, section $5.2.4$ (Pricing Under the Risk-Neutral Measure)): Given any $T>0$ and any $t\in[0,T],$ if $V(...
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2answers
566 views

Risk Neutral and Real World Valuations using Monte Carlo

Assume I'm an investor that wants to sell exotic put options. No one else is selling my kind of put option, so I need to determine my own "Market Price" through Monte Carlo simulation. I know that by ...
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1answer
74 views

T-Forward measure and tenors

As far as I understand, a T-forward measure is associated with a situation when a zero-coupon bond with the same maturity, i.e. $P(t,t+T)$, is used as a numeraire. However, given that the yield curves,...
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1answer
151 views

Pricing of compounded swaps

As far as I understand, a compounded swap rolls up individual payments into one final payment which becomes: $$ V(t_n) = N \prod_{i = 0}^{n-1}(1 + d_i L_i)-N $$ where $d_i$ is the day fraction for ...
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1answer
50 views

Call price in case of AOA

I have this exercice, and for the last question, i tried to say that with lower bound, $C > S_0 - Ke^{-rT}$ which is $-8$ something but it doesn't make sense so i don't know what to do. Could we ...
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64 views

Proving an Expectation

Assume the risk-free bond $B_t$ and the stock $S_t$ follow the dynamics of the Black & Scholes model without dividends. Consider the perpetual American put option with payoff $(K-S_\tau)^+$ when ...
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161 views

Proving a process is martingale under the Risk Neutral Measure

Show that for any $\lambda \in \Re$, the process $Y_{\lambda,t}$ defined as: $$Y_{\lambda,t} = (S_t/S_0)^\lambda e^{-(r\lambda-\lambda(1-\lambda)\sigma^2/2)t}$$ is a martingale under the risk ...
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74 views

Introducting a new probability measure

I'm trying to understand what means : $$ \frac {d \mathbb {\tilde{P}} }{d \mathbb P } \bigg\rvert_{\mathcal F_t }$$where $\mathcal F_t $ is a filtration I guess (not explicitely mentionned). they ...
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1answer
170 views

Floating Strike Lookback Call Option

Assume the risk-free bond $B_t$ and the stock $S_t$ follow the dynamics of the Black & Scholes model without dividends (with interest rate $r$, stock drift $\mu$ and volatility $\sigma$). If $r=\...
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2answers
71 views

Equivalent Martingale (/Risk Neutral) Measure Conditions

I am trying to understand EMM's and wanted to understand why we use EMM's over just martingale measures. The way we define EMM's is (for a simple one period model): Given a probability measure $\...
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44 views

Strictly increasing asset price under a risk-neutral probability measure?

I am reading a paper on option pricing under jump processes in continuous time. There is a section labeled examples where the authors work under a risk neutral probability measure and derive option ...
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1answer
85 views

Why Joshi defined option value to be discounted payoff using risk neutral expectation?

Currently I am reading Mark Joshi's The Concepts and Practice of Mathematical Finance. At page $59,$ the author mentioned the following. Instead of requiring that every portfolio should have ...
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Does an option need to be tradable for Black Scholes pricing formula to hold?

Given the classic Black-Scholes model, e.g. $dS(t)/S(t)=rdt+\sigma dW^{\mathbb{Q}}(t)$ with $S(0)=S_0$ and $dB(t)=rB(t)dt$ with $B(0)=1$, whereby $r$ and $\sigma$ are constants and $\mathbb{Q}$ ...
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1answer
78 views

Calculating the value of Beta - Martingales

Assume a risk free bond $B_t$and the stock St follow the dynamics of the Black & Scholes model. (with interest rate r, stock drift $\mu$ and volatility $\sigma$). Find $\beta$ such that the ...
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Deriving the risk-neutral pricing formula for the 2-state credit risk model

I am reading Interest rate models by Cairns—specifically the chapter on credit risk. Cairns introduces first the simple 2-state continuous time Markov model for credit risk—with the two states being "...
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43 views

Risk neutral measure in the binomial approximation of geometric Brownian motion

Suppose an asset is described by geometric Brownian motion with a drift, i.e. $$dS_t = S_t\mu dt + S_t \sigma dW_t$$ for a Wiener process $W_t$ and $S_0=1$. By some consequence of Girsanov's theorem (...
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39 views

Risk neutral valuation [closed]

In a world with three possible states (1, 2, 3) and three assets (A, B, C), the payoff matrix looks like this: $r_A;_1,_2,_3 = 110, 110, 110$ $p_A = 100$ $r_B;_1,_2,_3 = 100, 50, 40$ $p_B = 70$ $...
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1answer
76 views

Proof that we can price any derivative as the discounted value of its expected return under the risk neutral measure

I am reading a paper which tries to convey the intuition behind the Black-Scholes pricing formula. In that paper, the author states the following two things without proof, and I would like to know why ...
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single period security market with two assets

Consider a single period security market with two assets. Assume the current prices are There are two states at time one and the payoff matrix is 1.Suppose the investor believes that each state has ...
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1answer
81 views

Hedging an option on a non-traded asset in BS world

I have given the following task given. Suppose you are in a Black-Scholes World where you have the standard assets $$ dS_t = \mu S_t dt + \sigma S_t dW_t $$ $$ dB_t = r B_t dt $$ and now you also ...
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2answers
143 views

In BS option pricing, why is the drift rate of GBM equal to risk free rate for all stocks in risk neutral?

Can the drift rate μ depend on specific stock ? If not what is the rationale for the discounted Stock price to be a martingale ? \begin{align} & dS_t/S_t = \mu dt + \sigma dW_t \end{align} ...
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1answer
71 views

stochastic interest rate in binomial pricing model and in continuous models

Is the interest rate allowed to be truly stochastic in the binomial pricing model and in continuous models so that we are still able to switch to the risk-neutral measure? Shreve mentions multiple ...
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56 views

Switching to forward measure

I am trying to follow the wiki article on forward measure (https://en.wikipedia.org/wiki/Forward_measure), and can not understand how the change of measure was performed here: As I understand the ...
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1answer
191 views

Why use the risk-free rate for discounting in a risk neutral world?

I am reading Options, Futures, and other derivatives by John C. Hull. In the chapter on Binomial trees, he remarks: A risk-neutral world has two features that simplify the pricing of derivatives: ...
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47 views

State price deflator in the Vasicek model

I am trying to implement a simple bond pricing model using state price deflators in a Vasicek model. I am simulating paths of the processes $$\mathrm{d}r^{P} =\kappa^{P}(\theta^P - r^P(t))\mathrm{d}t ...
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Model-Free Option Pricing

From Breeden and Litzenberger (1978) and subsequent work, we may find the risk-neutral density $q_{S_T}$ of $S_T$ from European option prices - assuming there are enough traded options (e.g. SPX) via ...
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1answer
96 views

Valuation of Cash-Or-Nothing option

Studying options pricing, I'm stuck with the following problem: The price of a stock is described by the dynamic: $$dS_t = \mu\, dt + \sigma\,dW_t$$ Compute the fair price of a Cash or Nothing ...

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