A Modern Approach to the Efficient-Market Hypothesis
arXiv:1302.3001
Abstract
Market efficiency at least requires the absence of weak arbitrage opportunities, but this is not sufficient to establish a situation where the market is sensitive, i.e., where it "fully reflects" or "rapidly adjusts to" some information flow including the evolution of asset prices. By contrast, No Weak Arbitrage together with market sensitivity is sufficient and necessary for a market to be informationally efficient.
The content of this paper has been published under the title "Pricing and Valuation under the Real-World Measure" [arXiv:1304.3824]