United States, 515 F.3d 749, 751 (7th Cir. 2008) ("[Cemco] concedes that Notice 2000-44 and Treas. Reg. 1.752-6 scupper the entire class of offsetting-option tax shelters."); Desmet v. Commissioner, 581 F.3d 297, 299 (6th Cir. 2009) ("The petitioners do not dispute the ...