is t-bill interest subject to alternative minimum tax?
Interest that is exempt from the regular income tax may or may not be exempt from the AMT. It depends on complicated rules that are fully understood only by bond lawyers. Bonds that are not exempt from AMT pay a slightly higher rate of interest to compensate for the fact that they are not fully tax-exempt. If you invest in bonds that are not exempt under the alternative minimum tax, you are a candidate for AMT liability. Sources: http://www.fpanet.org/journal/articles/2004_Issues/jfp1004-art4.