(a) Joint account.--Any sum remaining on deposit at the death of a party to a joint account belongs to the surviving party or parties as against the estate of the decedent unless there is clear and convincing evidence of a different intent at the time the account is created. If there are two or more surviving parties, their respective ownerships during lifetime shall be in proportion to their previous ownership interests under section 6303 (relating to ownership during lifetime) augmented by an equal per capita share for each survivor of any interest the decedent may have owned in the account immediately before his death; and the right of survivorship continues between the surviving parties.

(b) Trust account.--At the death of the trustee or the survivor of two or more trustees, any sum remaining on deposit belongs to the person or persons named as beneficiaries, if surviving, or to the survivor or survivors of them if one or more die before the trustee or last surviving trustee, unless there is clear and convincing evidence of a contrary intent; if two or more beneficiaries survive, there is no right of survivorship in event of death of any beneficiary thereafter unless the terms of the account or deposit agreement expressly provide for survivorship between them.

(c) Other cases.--In other cases, the death of any party to a multiple-party account has no effect on beneficial ownership of the account other than that the rights of the decedent become part of his estate.

(d) Change by will prohibited.--A right of survivorship arising from the express terms of an account or under this section, or a beneficiary designation in a trust account cannot be changed by will.