On arbitrages arising with honest times

In the context of a general continuous financial market model, we study whether the additional information associated with an honest time τ gives rise to arbitrage profits. By relying on the theory of progressive enlargement of filtrations, we explicitly show that arbitrage profits can never be realized strictly before τ, while classical arbitrage opportunities can be realized exactly at τ and stronger arbitrages of the first kind always exist after τ. We carefully study the behavior of local martingale deflators and consider no-arbitrage-type conditions weaker than NFLVR. (based on a joint work with Monique Jeanblanc and Shiqi Song)