Nearly all joint accounts carry survivorship
Maryland's multiple-party account rule, part of the Financial Institutions Article, was enacted in 1992 specifically to resolve uncertainty in the common law about who owns funds left in a joint account after an owner dies. According to Maryland's own consumer guidance from the state Department of Labor, nearly all deposit accounts in the state that have more than one owner carry rights of survivorship as a result.
An open question at the state's highest court
Exactly how much of the balance the survivor gets, though, isn't fully settled. In a 2020 order, a judge on Maryland's Court of Appeals — the state's highest court — noted that neither that court nor the Court of Special Appeals had yet decided whether Maryland law should apply a "full ownership" presumption (the survivor gets everything) or an "equal shares" presumption (the funds are split evenly among however many owners there are) to a joint bank account. The note suggested a future case might eventually resolve the question, but as of that order, it remained open.
An agent isn't an owner
Not everyone named on a Maryland account signature card has ownership rights. Unless the account agreement says otherwise, someone named as an agent under a power of attorney, or as a "convenience person," can access the account to act on the owner's behalf and in the owner's best interests — but they have no ownership rights to the money, unlike an actual joint owner. Not every bank or credit union offers this kind of arrangement, so an owner who wants it may need to specifically look for an institution that does.
P.O.D. designations work alongside survivorship
A payable-on-death (P.O.D.) beneficiary designation is a separate tool from joint-owner survivorship. The named P.O.D. beneficiary has no rights to the account during the owner's life, and receives whatever remains only once the owner dies — useful for someone who wants to name a recipient without adding them as a co-owner with access to the funds in the meantime.
Life insurance and retirement accounts
Life insurance and retirement accounts like a 401(k) or IRA follow the ordinary rule: the named beneficiary receives the asset directly, outside probate, as long as they're alive when the owner dies. Either one becomes part of the probate estate only if no beneficiary was ever named, every named beneficiary predeceased the owner with no contingent beneficiary in place, or the policy or plan names the owner's own estate.