Yoram Margalioth (Tel Aviv University, Buchanan Faculty of Law), Eyal Sulganik (Interdisciplinary Center  Herzliya, Arison School of Business), Rafael Eldor (Interdisciplinary Center Herzliya, Arison School of Business) & Yoseph Edrey (University of Haifa) have published A Cost of Tax Planning, Rev. Law & Econ., Vol. 5 : Iss. 1, Article 7 (Apr. 9, 2009).  Here is the abstract:

Tax planning is an area of growing interest and this paper is an attempt to contribute to the small formal literature on this topic. The paper analyzes the case of tax planning that manipulates the tax system to impose lower effective tax rates on gains than on losses, and proves that such tax planning may provide firms with an incentive to produce more than the social optimum. This inefficiency is different from the general inefficiency entailed by income taxation, captured by the conventional notion of excess burden. A low asymmetric tax may be more distortive than a high symmetric tax rate.