# Tagged Questions

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0answers
27 views

### Negative probabilities - what are the two ordinary pgfs that correspond to the gf of a half-coin?

In Half of a Coin: Negative Probabilities, author considers pgf of a fair coin represented by random variable, $X = 1_H$: G_X(z) = E[z^X] = \sum_{x=0,1} z^xP(X=x) = (z^0)(1/2) + (z^1)(1/2) = \frac{...
1answer
90 views

### What if: Negative interest on an overdrawn bank account?

Theoretical question: Consider if a bank account had a -12% yearly interest rate, and an account was currently overdrawn to a balance of -$100. What would the bank do to the -$100 balance after one ...
2answers
126 views

### how negative rates (mr and rf) affect CAPM

I don't understand how the negative rates factor into this and what it means in the market ...
1answer
356 views

### Is inverted Japanese style curve persistent when negative rates are real / market - observed?

Are the inverted (Japanese style) governmental yield curves being a sign a recession/credit risk or should they be modelled as being due to a lack of liquidity? (...with such curves evolving into a ...
4answers
1k views

### How to avoid having negative volatility when applying Heston model?

When applying the Heston model to generate the sample volatility surface, some of the volatility value will be negative. I am just wondering what do practioners normally do with these negative value. ...
1answer
146 views

### Why for one year (and not two or three) government bonds (there is a spike for Switzerland & Denmark)?

On 10.10.2012, I have looked at the bond-rates and, both for Switzerland and Denmark, there is a discontinuity/spike at 1Y, as per below Switzerland: ON= -0.09, 1W= -0.180, 1M= -0.230, 3M= -0.2, 6M= -...
0answers
59 views

### Should portfolio be optimized by marking to the future than marking to market (excluding currencies)?

Observing the negative interest bonds in Switzerland, Denmark, GErmany the value of higher presently (credit-free) outgoing cash flows seems less important than the value of lower future (credit-free) ...
0answers
84 views

### Neglect the positive values in negative interest rates modelling?

The magnitude of the negative interested rate should vary correlated with the increase in fixed assets prices and with cross-currency basis spreads. Could their volatility / correlation coefficients,...
1answer
81 views

### Separated software and physical cash flows modelling and pricing to be used with negative interest rates?

The physical cash presence in the final transactions is one of the issues in the presently observed negative interest rates bonds. Such a situation has historically been modelled within the "liquidity ...