# All Questions

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750 views

### Python Backtesting Framework Similar to Quantstrat

I use Quantstrat heavily for strategy research and optimisation. I have two Python developers about to join my team and would like to use it as an opportunity to diversify our research tools so we are ...
234 views

### Libraries for calculating options strategy-based margin

Hopefully, this is an acceptable question in this forum, even if it isn't analytically focused. As part of an effort to analyse the effect of different option trade structures on a portfolio, I need ...
281 views

255 views

### Transition densities in the Heston model

Knowing the Characteristic function $\Phi_{T,t} = \mathbb{E} [ e^{i u S_T} | S_t, V_t]$ (or equivalently, the Laplace transform) of an affine process, it's possible to know the distribution of the ...
250 views

### Applications of distance correlation

This question mentions distance correlation. Where has this concept been applied to financial data and provided new insight? Do you know any examples or references?
135 views

### Feller Condition (Cox-Ingersoll-Ross) source

For the Cox-Ingersoll-Ross model $$\text{d}r_t = a(b-r_t)\text{d}t+\sigma\sqrt{r_t}\text{d}W_t$$ the condition (referred to as "Feller condition") $$2ab\geq\sigma^2$$ ensures that the solution is ...
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### Arbitrage free smoothing of volatility smile - cubic spline - implementation procedure

I am studying the paper Arbitrage-Free Smoothing of the Implied Volatility Surface, from Matthias R. Fengler (https://core.ac.uk/download/pdf/6978470.pdf). The problem I want to solve is much simpler ...
50 views

### Quantitative and regulatory aspects of portfolio integration in IRB credit portfolios

Say bank A buys a credit portfolio "B" (e.g. corporate loans or retail mortgage, ...) from bank B. Bank A fulfills the the requirements of CRR (capital requirement regulation) for its existing ...
104 views

### Estimation of right truncated poisson process

I have following problem: Imagine I generate large number of homogenous poisson process sample paths (by sample path I mean a sequence of arrival times $\tau_i$ all with the same intensity. However ...
107 views

### Mathematical Representation of Adaptive Markets Hypothesis

It has been about 13 years since Andrew Lo published The Adaptive Markets Hypothesis. It provides valid criticism to Efficient Markets Hypothesis and brings lots of innovation over it. Unfortunately, ...
337 views

### How do you actually solve a stochastic HJB equation in practice?

I've read a number of recent papers on market making. Nearly all of the more recent papers focus on defining the problem in terms of a state and action space, deriving the relevant HJB equations and ...
284 views

### What are the essential characteristics of asset prices?

I think the question has already been asked about stylized facts of asset returns; this question regards the essential characteristics and normative assumptions used to evaluate asset prices. I.e., ...
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### Stress testing covariance

Going one level beyond stressed scenarios, to parameters e.g. for a VaR measure: what are the most common approaches for stressing a covariance/correlation matrix, especially taking portfolio exposure ...
424 views

### is there a mapping from Altman Z-score for private companies to bond ratings or probability of default?

On wikipedia, there is a formula to calculate the Altman Z-score for private companies: Z-score estimated for private firms: T1 = (Current Assets − Current Liabilities) / Total Assets T2 = Retained ...
1k views

### Asymmetric Volatility Modeling (Interpretation)

I am currently writing a paper on asymmetric volatility modeling of brent, gold, silver, wheat, soybean and corn from 1986-2012 and divided them into 4 sub-sample periods (i.e. 1986-1991, 1991-1997, ...
198 views

### Arbitrage free price of a derivative when the price is collected over the lifetime of the derivative

Let $X_t$ be an american style financial derivative with random exercise time $T$ where $t$ and $T$ belongs to some finite set $A$. Buying this derivative requires the buyer to pay $p_t$ up to time $T$...
948 views

### Is there a standard method of scaling alpha forecasts to t-cost estimates?

Given a set of monthly alpha forecasts (i.e. standardized z-scores from a multi-factor return model) and a non-linear market impact model (or more specifically, its piecewise-linear approximation), is ...
214 views

### How companies choose earnings release dates, & effect on Implied Volatility

A company's earnings release date significantly affects weekly or monthly option prices/implied volatility. For companies that typically release earnings on the cusp of monthly options expiration, ...
410 views

### Taking into account the correlation in Barrier options on a Basket

In a Barrier option (where the contract cancels when the underlying hits the barrier) I succesfully found the way to compute the probability of a single underlying touching the barrier (with constant ...
249 views

### Significance testing of average returns from Sharpe ratio

I'm aware that one way to do significance testing on a strategy is based on the sampling distribution of its Sharpe (see, e.g., Lo, 2002 and Opdyke, 2008). However, it appears to me that there's ...
80 views

### Distribution of portfolio values with constant spending rate

If your portfolio is invested in an asset that follows a geometric Brownian motion, and you withdraw a constant dollar amount at the beginning of each year, is there an approximate analytical ...
61 views

### Implied Funding/Borrow Costs in Short-Dated ETF Option Prices

I'm struggling with some anomalous behavior in an analysis I'm running and was hoping for some advice/insights. I'm attempting to extract the implied funding/borrow costs from ETF option prices (say ...
130 views

### SABR Question: Why does the market take the beta parameter as a constant?

SABR Question Why does the market take the $\beta$ parameter as a "constant"? I see most brokers quoting SABR parameters nowadays. I've seen many banks use $\beta$=0.5 as a rule. I've seen quants ...
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### Expected turnover from rebalancing

If you have a target weights for N assets with monthly returns that are drawn from a multivariate normal distribution with known means and covariances, is there an exact or approximate analytical ...
105 views

### Merton's portfolio problem with constraints

Suppose the investor can invest in a Black-Scholes market with one risky asset $S$ with drift $\alpha$ and volatility $\sigma$ and a riskless asset $B$ with a riskless rate of return $r$, and the ...
279 views

### Interpreting Fama-French factors for the German stock market

I calculated the Fama-French five factors myself for the German market. Most of my results align well with prior research, except one thing: When i do the calculations for the sub-period from 2011 to ...
335 views

### Risk management tools for long term Gamma/Vega sellers subject to margin calls

TL;DR: if you're a retail investor and you systematically sell long-term vertical spreads while staying Delta-neutral, your main risk comes from Vega and the Gamma of opening gaps that can throw you ...
46 views

### Martingale property of inhomogenous poisson process

I have found this martingale property for an inhomogenous poisson process with intensity $\lambda(s)$ which I don't know how to prove. The text itself advises: "proceed using Monotone class theorem". ...
332 views

### Gyöngy Theorem Proof

Can you please point me to a publicly available text that discusses the proof for the Gyöngy Theorem? Gyöngy, I. (1986), “Mimicking the One-Dimensional Marginal Distributions of Processes Having an ...