Joint tenancy is an estate which requires four unities: title, time, interest and possession.  Essentially, joint tenancy is where one estate is owned by two or more persons holding title under the same instrument.
“The interests of joint tenants are equal. They own the half or part and the whole, ‘per my et per tout.’"  Each joint tenant is considered to own an undivided share of the entire property.
a. See D’Arcy v. Buckley, 71 Bucks Co. L. Rep. 167 (1997) (In this case, the parties purchased property as joint tenants with right of survivorship. Plaintiff contributed five times more than defendant had towards the purchase price. In a partition action, Plaintiff sought credit for the full amount of his superior contributions. The Court held that, in the absence of fraud, the working of the deed operated to convey a one-half interest to each of the joint tenants. The decision relies the following authority: Masgai v. Masgai, 460 Pa. 453, 333 A.2d 861 (1975) and DeLoatch v. Murphy, 369 Pa. Super. 255, 535 A.2d 146 (1987). Plaintiff argued, to no avail, that he did not intend to make a lifetime gift to defendant.
A conveyance of two or more persons who are not husband and wife is presumed to create tenancy in common and not joint tenancy, unless clear intent to the contrary is shown.  This can hold true even when the unmarried persons are listed on the deed as husband and wife. 
Land held in joint tenancy does not, of itself, carry right of survivorship between the joint tenants.  “Right of survivorship" means the interest of a deceased joint tenant passes by operation of law to the surviving joint tenant(s), immediately upon death. In order for joint tenants to have the right of survivorship in intended. 
a. A Superior Court case held that a right of survivorship is not available when the percentage of ownership varies between co-owners. The Court reasoned that the co-owners were tenants in common because they lacked one of the four unities (no unity of interest), and therefore, right of survivorship was unavailable. 
b. No particular language is required in order to create the right of
survivorship.  It is advisable to use such language as: “as joint tenants with right of survivorship", or “as joint tenants with right of survivorship and not as tenants in common."
c. But see, Fenderson , where a brother who contributed to the purchase price of a residence, but whose name was not included on the deed, was entitled to a resulting trust as a joint tenant with right of survivorship.
- Because the interest passes by operation of law, the right of survivorship cannot be defeated by a will or by laws of intestacy.
a. In fact, probate or will-contest avoidance is often the motivation with an individual (e.g., a parent) takes property out of single ownership and creates joint tenancy with an intended beneficiary (e.g., a child). Often overlooked in these situations are the potential tax savings of having the property remain in single ownership. If the property’s fair market value is significantly greater than its adjusted basis (which is often the case), the owner should consider the capital gains tax which the beneficiary would owe at the sale of the property.
- As a general rule, a joint tenancy can be severed by a an action which destroys one of the four unities. 
a. In joint tenancy with right of survivorship, the right of survivorship remains unless severance becomes final and complete before the death of a joint tenant.
b. A joint tenancy is broken when one tenant transfers his interest, has his interest executed upon by creditors, or obtains a judgment of partition. Joint tenancy is severed when an agreement of sale is entered into, because this creates a new equitable ownership interest in the buyer.
A joint tenancy does not terminate upon entry of a money judgment against a tenant, nor does filing for bankruptcy sever joint tenancy. The joint tenancy is severed by execution or an attempt to sell the property. 
Commencement of a partition action does not sever the joint tenancy, because the partition action may be abandoned up until the time judgment is rendered.  Therefore, when a tenant dies during the pendency of a partition action, the decedent’s share will pass to the surviving tenant by operation of law. 
If there are more than two joint tenants, and the remaining joint tenants are not, as between themselves, affected by the act which severs the joint tenancy, then the remaining joint tenants may still hold their interests as joint tenants in relation to one another.  The severing joint tenant or his successor will hold his interest as tenant-in-common with the remaining tenants. 
Estate of Kotz, 486 Pa. 444, 458 A.2d 524, 531 (1979).
Estate of Kotz, supra.
Zomisky v. Zamiska, 449 Pa. 239, 296 A.2d 772 (1972).
First Federal Savings and Loan Association of Greene County v. Porter, 408 Pa. 236, 183 A.2d 318 (1962).
68 P.S. § 110.
In re Michael’s Estate, 421 Pa. 207, 218 A.2d 338 (1966).
Edel v. Edel, 283 Pa. Super 551, 556-7, 424 A.2d 946 (1981).
Pa. Bank & Trust Co. v. Thompson, 432 Pa. 262, 247 A.2d 771 (1968); Maxwell v. Saylor, 359 Pa. 94, 58 A.2d 355 (1948).
Fenderson v. Fenderson, 454 Pa. Super. 412, 685 A.2d 600 (1996).
In re Beniger’s Estate, 449 Pa. 373, 296 A.2d 773 (1972).
In re Anthony, 82 B.R. 386 (W.D. Pa., 1987).
In Clingerman v. Sadowski, 513 Pa. 179, 519 A.2d 378 (1986), the Supreme Court allowed a tenancy by the entireties to be severed by the filing of a partition action. The Court distinguished the case from cases involving joint tenancies.
Sheriden v. Lucey, 395 Pa. 306, 149 A.2d 444 (1959), DeLoatch v. Murphy, 369 Pa. Super 255, 535 A.2d 146 (1987).
Stranger v. Epler, 382 Pa. 411, 115 A.2d 197 (1955).
American Oil Co. v. Falconer, 136 Pa. Super. 598 (1936).