What is a key feature that characterizes joint accounts?

A key feature of joint accounts is equal ownership by all parties involved. This means that each individual listed on the account has an equal claim to the assets held within it. In practice, this characteristic ensures that all parties have the same level of access and control over the account and its transactions. The equal ownership model creates a shared responsibility among the account holders, which is essential for joint management of financial assets.

The other options do not capture the essence of joint accounts effectively. For instance, having investment decisions made by a single party would contradict the fundamental nature of joint accounts, where all holders typically share in decision-making. Pro-rata sharing of investments might imply a different kind of arrangement or agreement among parties that is not inherent to all joint accounts. Lastly, while some joint accounts might enable automatic income distribution, this is not universally applied and does not serve as a defining characteristic of joint account ownership. Thus, equal ownership by all parties stands out as the defining feature.