- 2012 (2) (entfernen)
- Artikel in einer Zeitschrift / Postprint (2) (entfernen)
- Keep on smiling? The pricing of Quanto options when all covariances are stochastic (2012)
- The paper introduces a model for the joint dynamics of asset prices which can capture both a stochastic correlation between stock returns as well as between stock returns and volatilities (stochastic leverage). By relying on two factors for stochastic volatility, the model allows for stochastic leverage and is thus able to explain time-varying slopes of the smiles. The use of Wishart processes for the covariance matrix of returns enables the model to also capture stochastic correlations between the assets. Our model offers an integrated pricing approach for both Quanto and plain-vanilla options on the stock as well as the foreign exchange rate. We derive semi-closed form solutions for option prices and analyze the impact of state variables. Quanto options offer a significant exposure to the stochastic covariance between stock prices and exchange rates. In contrast to standard models, the smile of stock options, the smile of currency options, and the price differences between Quanto options and plain-vanilla options can change independently of each other.
- Spread ladder swaps - an analysis of controversial interest rate derivatives (2012)
- This article analyzes spread ladder swaps traded by Deutsche Bank to several medium-size companies and municipalities. The value of these contracts is highly sensitive to correlations between forward rates. For a contract that was challenged by the medium-size company Ille at the Federal Court of Germany, it turns out that the derivative was originated at a negative market value of −90,000 to −115,000 euros (depending on the number of factors used in the model). Moreover, the model correctly predicts the range for the terminal payment after an adverse development of the term structure of approximately 567,000 euros. We also investigate a product feature that limits the upside potential from the viewpoint of the customer and show that it has a substantial impact on market values. According to the judgment handed down by the court, the bank should have informed the customer about the market value of the product in light of special circumstances. This raises questions as to which products must meet this requirement. Moreover, especially for exotic contracts, market prices are mostly model prices: for spread ladder swaps, substantially different prices are obtained even when investors agree on the variance/covariance matrix but disagree on the number of factors to apply in an implementation of a model.