???? - 1779
Alexander Isaaks [sic] Keyser appears as one of more than a dozen London merchants in the recitation of a deed of 08/06/1771 whereby William Byam of St Vincent sold annuities totalling £1010 p.a. secured on his estate and named enslaved people in St George on St Vincent in exchange for £10,040. The schedule specifying the annuitants referred to in the deed is missing, but the narrative suggests that Alexander Isaks Keyser and others (including his partner Abraham de Mattos Mocatta) grouped together in the third part of the deed were the purchasers of the annuities.
EAP 668 Deed Book 1785, British Library, EAP688/1/1/1, https://eap.bl.uk/archive-file/EAP688-1-1-1 pp. 371-389. The deed of 1785 deals with the efforts of the trustees Harry and Isaac Thompson to better secure the annuities by increasing their control of the estate.