美国有很多种business entity,而且都是和州法有关,一般来说一个州会允许以下business entity
sole proprietorship (个体户),partnership (合伙企业)包含general partnership and limited partnership,Limited Liability Company(有限责任公司),S-Corp,Corporation.
五花八门的business entity在联邦税务上,只有两个treatment,passthrough taxation和corporate taxation。
passthrough就是公司收入完全落到个人或者合伙人或者股东身上,按照股东收入缴税。个体户和partnership肯定是passthrough,S-Corp和LLC可以选择passthrough还是corporate taxation,Corporation肯定是corporate taxation。
corporate taxation是指公司收入单独交公司税,然后剩下的分红发到股东手里,再交一次股东的收入税。LLC and S-Corp could choose this as well, if it makes sense in company's finance.