MAMRAM (or Mamran ; ממר״ם, ממר״מ, ממרנ״י, ממר״א and at times abbreviated to מ״מ), a form of promissory note distinguished by its brevity. In Hebrew sources it is mentioned for the first time during the 12th century in the tosafot of *Elhanan b. Isaac of Dampierre to the tractate Avodah Zarah. There is evidence of its use in Poland from the 14th century at least, but it was only during the 16th century that it became the distinctive promissory note used by Jewish merchants in their internal trade. There are various opinions on the etymological origin of this term, the most important being: a derivation from the Hebrew word המיר (hemir, "to change"); a contracted form of the Latin in memoriam; and a derivation from the word membrana, which in medieval Latin signified a scrap of parchment. The signature of the debtor appeared on one side of the document, while, on the other, in the same place as the signature, the sum owed and the date of payment were recorded. According to the regulations of the community councils, the document had equal validity with the ordinary handwritten promissory note even though the lengthy traditional formula was absent. Since the name of the creditor was not mentioned in the mamram, it was payable to the person who presented it to the debtor. As a result, the mamram was purchased by one person from another by simple transfer without any written documentation. The brevity of the mamram and the possibility of its easy transfer gave it a great advantage over the ordinary bill, encouraging its popularity. It was most common in Poland, especially during the 16th century, and the trading of mamramim became a frequent occurrence.
Another kind of mamram frequently employed in Poland during the 16th century was the blank mamram (in Polish membran goły). Its principal feature was that neither the amount of the debt nor the date of payment were mentioned. The signature of the creditor appeared on one side and the other side was blank. It is evident that a document of this kind could only exist in a society where the honesty of the debtor was taken for granted. The blank mamram came to satisfy the demands of the commerce practiced by the Jews of Poland during that period and it was particularly suited for use at the large fairs then held in the country. The merchant did not bring large sums of cash to the fairs because of the many dangers attendant on his journey and many deals were concluded at the fairs on short notice. Thus the merchant was in need of credit during that time and the mamram document satisfied his requirements. Through its use merchants could borrow unlimited sums, which in turn permitted the orderly development of business. The mamramim thus fulfilled the functions later provided by banks. The blank mamram was also different in that it was signed not by the debtor but by the person providing the credit. When in need of funds, the debtor sold it and thus received the amount he required. Because the halakhic basis of the blank mamram was highly dubious, some eminent rabbis objected to it and invalidated it and its use. Most authorities sanctioned it, however, because "it has already become the custom in these lands to collect by it according to the regulations of the countries." It was still in use among Polish Jews in the first half of the 19th century.
P. Bloch, in: Festschrift… A. Berliner (1903), 50ff.; A. Gulak, Yesodei ha-Mishpat ha-Ivri, 2 (1923), 142ff.; idem, Oẓar ha-Shetarot (1925), 214ff.; S. Dubnow, Pinkas ha-Medinah (1925), index; Halpern, Pinkas, index; idem, Takkanot Medinat Mehrin (1952), index; S. Lipschutz, Ḥemdat Shelomo, Ḥoshen Mishpat (1969); M. Breger, Zur Handelsgeschichte der Juden in Polen im 17. Jahrhundert (1932), 45ff.; J. Katz, Tradition and Crisis (1961), 70ff.
"Mamram." Encyclopaedia Judaica. . Encyclopedia.com. (January 22, 2019). https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/mamram
"Mamram." Encyclopaedia Judaica. . Retrieved January 22, 2019 from Encyclopedia.com: https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/mamram