We investigate financial markets under model risk caused by uncertain volatilities. For this purpose we consider a financial market that features volatility uncertainty. To have a mathematical consistent framework we use the notion of G-expectation and its corresponding G-Brownian motion recently introduced by Peng (2007). Our financial market consists of a riskless asset and a risky stock with price process modeled by a geometric G-Brownian motion. We adapt the notion of arbitrage to this more complex situation and consider stock price dynamics which exclude arbitrage opportunities. Due to volatility uncertainty the market is not complete any more. We establish the interval of no-arbitrage prices for general European contingent claims and deduce explicit results in a Markovian setting.
What does the financial market pricing do? A simulation analysis with a view to systemic volatility, exuberance and vagary
Biondi et al.(2012)开发了一个分析模型,以研究股票市场价格形成随时间推移的新兴动态特性,能够捕捉重要的程式化事实。这些后一种性质证明是敏感的基本信息提供的监管制度,以及对市场的信心条件之间的实际和潜在的投资者。以按市价(公允价值)计量交易证券为基础的制度虽然在市场价格和基本信号之间产生较高的线性相关性,但也涉及较高的市场不稳定性和波动性。这些制度还在市场信心空间的某些区域引发更多相关的市场繁荣和反复无常的事件,在这些区域进一步出现较低的市场流动性。