What is the impact of “Dina D’malchusa” or “normative customs” in the United States, in which married women can own separate property and have separate bank accounts, and the Shulchan Aruch’s law of “Nichsei Milug”?
Several authorities write that in the matter of nichsei milug, which is not to the benefit of the malchus (the king, or the authorities), the principle of dina demalchusa does not apply. However, if the couple had clear intentions to divine wealth according to the principles of the law, then the principles of the law or “normative customs” might apply.
In general, the concept of nichsei milug does not mean that the wife cannot have a separate bank account or property, but only that the husband has the right to the “fruit” (income generated by) of the property.
Sources: See Shulchan Aruch, Choshen Mishpat, end of 368; Heishiv Moshe 90; Pischei Choshen, Ishus chap. 8, p. 317; Orchos Hamishpatim, p. 174.