In general (wildly general), legal scholars say that you are entitled to use any name you wish, even when contracting, provided you are not doing something that

In general (wildly general), legal scholars say that you are entitled to use any name you wish, even when contracting, provided you are not doing something that's illegal (such as perpetuating a fraud, theft, or some other form of deceit). States have a statutory name change process so that your name can be deemed recognized but, otherwise, your use of a name is solely up to you and the willingness of others around you to accept it. If you'd like to read a rather well done paper on it, check out this one from the UCLA Law Review: http://www.uclalawreview.org/pdf/57-1-7.pdf http://www.uclalawreview.org/pdf/57-1-7.pdf (By way of example, I was born "Firstname Middlename Lastname." I use an abbreviated form of my middle name in common usage, so let's say "Mid Lastname." A couple of my credit accounts have "Mid Lastname" on them, as does one of my utility bills, because they accepted my preference for using that name. Others have "Firstname Lastname" or "Firstname M. Lastname" because that was the policy of the business when I opened them. They are all equally valid and equally binding on me because I am the one who did those acts and I can demonstrate that I am. Why have I not done the statutory name change process in my state to formally adopt "Mid Lastname" as my recognized name? Eh, haven't felt like it.)