# Tag Info

Accepted

### Quantlib-Python: use zero rates to get the originally bootstrapped curve

To retrieve the original curve, you need to use the same key tenors of the original curve and with the same interpolation. For instance, when you create the original curve as: ...

Accepted

### How does Bloomberg arrive at stub rate for swaps/floaters?

Basic money markets arithmetic. Using day count convention ACT/ACT, 01 Dec 2016 to 13 Jan 2017 is 43 days, ...
Accepted

### What techniques can be used to get the missing maturities from the CMT yields?

The CMT yields published by the Fed/US Treasury are par yields calculated using a cubic spline model. In other words, these are the yields to maturity as well as coupon rates on bonds whose theoretic ...
Accepted

### Zero Curve Interpolation Does Not recover Node point input rates

For historical reasons, the curve implementation goes through discount factors to calculate zero rates, no matter what the underlying representation is; see https://github.com/lballabio/QuantLib/blob/...

### Interpolating on the BS parameters and injecting in the BS formula vs interpolating directly on option prices

The best way is to interpolate in volatility space. The reason is because it is closer to the intrinsic pricing of the option, and it is less likely to produce an arbitrage. Like Alex C noted in the ...

### Getting option volatility off vol surface

See the paper "FX Volatility Smile Construction, Dimitri Reiswich and Uwe Wystup" http://janroman.dhis.org/finance/FX/FX%20Volatility%20Smile.pdf for a comprehensive construction of the FX volatility ...

### Quantlib ZeroCurve interpolation

The data stored in the object is adjusted such that compounding is Continuous and frequency is NoFrequency. The C++ source code ...
Accepted

### How do people 'lookup' values from calculated surfaces?

A linear interpolation in 2d is not much more complicated that in 1d: \begin{align} \color{red}{f(x,y_i)}&=\frac{f(x_i,y_i)(x_{i+1}-x)+f(x_{i+1},y_i)(x-x_i)}{x_{i+1}-x_i}\,,\\[3mm] \color{red}{f(x,...
Accepted

### What kind of interpolation is this?

I don't understand why they not just use $$\tag{1} D=\sigma^2(t_k)(t_{k+1}-t_k)$$ which leads to the theoretically correct variance of $W_t-W_{t_k}$. Rewriting (3) gives for the increment over the ...

### Simple approach to interpolate option surface

As has been said in the comments, unless you are working with an asset class that has a second dimension, i.e, swaptions where you have not only the option expiry but also the underlying tenor, a ...

### Curve optimization to predict monetary policy path (OIS Curve)

The idea behind this is no different to the other currencies. I will just make up some data. First assume a Curve that has constant overnight forward rates between ...
1 vote

### How do I calculate Hull White's Theta from the discount curve?

In practical situations you will never know $P^M(0,t\pm\epsilon)$ for a continuum of $t$ and $\epsilon\,.$ In other words, $\theta$ will practically always depend on an interpolation method between ...
1 vote
Accepted

### Volatility surface interpolation for Black-Scholes delta hedging

A cubic polynomial curvature would be the most simple one.Otherwise,many practitioners are actually using a Gaussian process interpolation,which is more sophisticated.
1 vote

### Interpolating a yield from two yields (giving more weight to one of the two)

If these are risky (e.g., corporate) bullet bonds, then I would not interpolate the yield directly, because their yield has two distinct components: a risk-free rate and an additional spread (to ...
1 vote

### Getting a daily forward OIS rate curve with QuantLib in Python

The problem is that in the first step, you are only fetching the forwards for the curve nodes. You could make a daily schedule and get forwards directly from the curve for each date. ...
1 vote

### monotone convex interpolation using QuantLib

Not sure why you would want this because you have quotes for EUR6M and EUR3M directly (Swap vs 3M and 3M Futures). Also not sure, why you would have more nodes for the 3M since both swaps and basis ...
1 vote
Accepted

### Quantlib Natural Cubic spline yield curve

QuantLib has several interpolation methods for yield curves. Here is an example of a few methods for Portuguese Government Bonds to get you started. ...
1 vote

### Linear Interpolation around End of Month (EOM) for IRS with standard rolls

The legal definition of the swap is given by the ISDA confirm which will specify “Floating Rate Option” USD Libor with a maturity of 3 months. If so, this means you always take 3month Libor no matter ...
1 vote
Accepted

### Raw interpolation when the desired term is out of the know originals

What you are interested in is called extrapolation. In other words, you want to "extend" your function $r$ for $t < t_0$ and $t > t_n$. What the author ...
1 vote

### Estimating daily volatility of unevenly/irregularly spaced time series data

A simple estimate of the volatility $\sigma$ of an asset given $N$ samples of asset prices $S_i$ at times $t_i$ is:  \sigma^2 = \frac{1}{N} \sum_{i=1}^{N} \frac{\log(S_i / S_{i-1})^2}{t_i - t_{i-1}}...
1 vote
Accepted

### Linear interpolation Discount factors

I don't recommend linear interpolation of DFs and the swap rates you are applying this to are either against 12M libor which is illiquid or you are not accounting for Quarterly or Semi-Annual floating ...
1 vote

### Best method for interpolating yield curve? [Multiple questions]

A few observations: the coupon yield curve is never going to be smooth, because a high coupon Treasury and a low coupon Treasury with the same maturity do not yield the same. That's because in an ...

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