Tax advisers are often asked to project tax expense arising from an anticipated transaction by multiplying book income by the statutory tax rate.  This seems like an easy task, but a reliable answer is anything but straightforward, as more jurisdictions enact alternative minimum tax (“A.M.T.”) regimes to protect the tax base.  Galia Antebi, Kenneth Lobo, and Stanley C. Ruchelman explain how the A.M.T. works in the U.S. and how a comparable tax in Puerto Rico lead to a proposed 132% effective tax rate.