A mortgage to two or more persons, unlike a deed, is held by them as joint tenants. See G.L.c. 184, §7.
Also, it appears that assignees of a mortgage hold the mortgage as joint tenants. See Webster v. Vandeventer, 72 Mass. 428 (1856) where it is said, "Two or more joint mortgagees are joint tenants, and not tenants in common, of the mortgaged lands. So, doubtless, are two or more assignees of a mortgage, especially if the mortgage is assigned to them as trustees of a third party. Co-trustees are joint tenants. Appleton v. Boyd, 7 Mass. 131. Hill on Trustees, (2d Amer. ed.) 441, 442. Rev. Sts. c. 59, § 11." In Webster the mortgage had been assigned to two trustees of an unincorporated Society. The ruling of the court, therefore, was limited to an assignment of a mortgage to trustees, however the general statement by the court is not limited to trustees.