# All Questions

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### What's the point of discounting in risk-neutral pricing?

Let $\phi$ be a self-financing strategy that replicates a time $T$ option payoff $X$ on stock $S$. By definition of a trading strategy, $\phi$ is previsible. Finally, let $V_t$ be the time $t$ value ...
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### Yield and interest rate? [on hold]

Are they the same thing? Is yield the annualized return rate? Why when yield rise, yearly return increases but price falls?
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### Expected Utility and $\log$

I've just started reading about expected utility and utility functions and have the following question. $\textbf{Question:}$ An investor has an initial wealth of 100 and a utility function of the ...
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### Markowitz portfolio optimization question

I am studying the Markowitz portfolio optimization theory, and I just wanted to ask if I understood this correctly. For a stock portfolio we distinguish two kinds of risks: an unsystematic risk, which ...
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### Need for Binomial Representation Theorem

In some texts (e.g. Baxter & Rennie, Shreve I) the binomial model is first constructed using the usual backward induction argument, and it is concluded that by no-arbitrage the time $t$ value of a ...
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### Portfolio volatility

Problem True or fale? The stock of a firm has an expected return of 10%, and a volatility of 10%. The weight of the stock in a portfolio is 5%, and the correlation of the stock’s return with the ...
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### Option Pricing under Jump Diffusion Models

I was wondering what the overall approach/intuition behind how to price options under Jump Diffusion Models. My understanding is under Diffusion models such as Geometric Brownian Motion (Black ...
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### Is the Binomial Tree Model not self-financing?

Consider a 2-period binomial tree where the derivative price is $f$ and the stock price is $S$. Also, let the bond be deterministic with continuous growth rate $r$ and initial value $B_0$. binomial ...
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### How to test if two portfolios have the same composition

I'm facing two different portfolios in CAPM framework derived as $$\omega_P=\Sigma^{-1}\frac{E(r)-r_f}{H}(\mu-\iota'r_f)$$ on the same assets but for example on different time sample or on the same ...
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### Is the Altman Z-Score broken?

When I try to predict future returns with with the Altman Z score, it fails. That would likely not be the case if it predicted bankruptcy well (e.g. the Piotroski F score). It seems to predict ...
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### Is R being replaced by Python at quant desks?

I know the title sounds a little extreme but I wonder whether R is phased out by a lot of quant desks at sell side banks as well as hedge funds in favor of Python. I get the impression that with ...
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### High frequency price forecast model ARMA GARCH or another?

Can you reccomend model for high frequency data (1 second and less) (returns and volatility forecasting)? Most papers use ARMA, GARCH etc in 1 minute and lower time frame. PROBLEM ARMA does not know ...
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### Why is the black-scholes model arbitrage free when σ>0?

I want to show that: if $σ$ is positive then there is no arbitrage in the model, even if $r > µ$. Whilst I have satisfied this for $r > \mu$, I cannot see why the conditioning on $\sigma>0$ ...
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### Negative time value european options

I have a basic question for which I feel like I should have found the answer by googling it, but I didn't get a definitive answer, so here I am: Can the time value for a plain vanilla (European) ...
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### Why dynamics of local volatility is wrong?

In Dupire's local volatility model, the volatility is is a deterministic function of the underlying price and time, chosen to match observed European option prices. To be more specific, given a ...
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### Show that the equation solves the Black-Scholes PDE

I have the solution as given Based on this, I have to show that this solves the Black-Scholes formula It means that I should take the partial derivatives of the solution above and then receive the ...
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### Why can a CDS indices be used as a bond market index?

I don't understand why the iTraxx indices family, which are credit default swap indices, are in practice often used to gauge the bond market. How are CDS prices related to bonds prices ? And what ...
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### Computing Value at Risk for portfolio in R

I know how to compute VaR with long positions using PerformanceAnalytics. What about a portfolio consisting in two equities A and B, 100 USD long positions in each, and 2 stock options for the same ...
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### Z-Score calculation for a win-loss streak

I am trying to find the correlation between wins and losses by applying Z-Score according to formula attached below. I put them in an array by assigning 1 to wins and -1s to losers. I am trying to ...
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### Cointegration tests: how do you accurately test the necessity of time trends in the Johansen and Engle-Granger Test?

Is there a correct and up to date procedure? I just run the equation in VEC form and test the significance of the time trends? What are the possible problems that I should be aware of?