ORS § 105.920
There shall be a form of co-ownership of personal property known as joint tenancy. A joint tenancy shall have the incidents of survivorship and severability as at common law. A joint tenancy may be created only by a written instrument which expressly declares the interest created to be a joint tenancy. It may be created by a transfer or bequest from a sole owner to others, or to the sole owner and others; or from tenants in common or joint tenants to others, or to themselves or some of them, or to themselves or any of them and others; or from spouses married to each other, when holding title as community property or otherwise, to others, or to themselves, or to one of them and to another or others. A transfer or bequest creating a joint tenancy shall not derogate from the rights of creditors.
ORS 105.920