Could the ex- signify 'without' in the OED below? Or did English misuse it in 1b below?
1. In Latin phrases (some of which are in English written as single words), as ex animo n., ex parte adj., extempore v., ex-voto n., etc.
[...]
b. With sense ‘without,’ ‘exclusive of’; esp. in phrase ex dividend (abbreviated ex div. or x.d.), used with reference to sales of stocks or shares to indicate that the dividend next to be paid is not included in the sale. So formerly ex interest (abbreviated ex int., ex in., x.i.); also ex new (ex n., x.n.), intimating that the right to an allotment of new shares or stock is not included in the sale.
I descry nothing on 'without' on pp 690-691 on Oxford Latin Dictionary (2012 2 ed).
My research on 'ex-dividend date' spurred this question.