RSA 383-B:4-405 Joint Accounts.

A person or persons may establish a deposit account at a state or foreign depository bank doing business in this state pursuant to a written agreement. The written agreement shall govern the rights of any person who is named as an owner of the account. In the absence of a written agreement, if 2 or more persons are named on a deposit account as owners, the account shall be payable to any owner, and in the event of death, to the survivor or survivors of them. The survivors shall be entitled to ownership of the account whether or not (i) the funds deposited were the property of only one or some of the owners, (ii) at the time of the making of such deposits there was any intention on the part of the owners making such deposit to vest the other owner or owners with a present interest therein,