Section 7 of the Transfer of Property Act, 1882 provides that every person competent to contract i.e. a major and of sound mind or is not disqualified by law for contracting. Therefore even the interest of a co-owner or co-sharer can be sold, mortgaged, leased to another co-sharer or to a stranger. The fact that the partition has not taken place by metes and bounds , does not stand in the way of the interest of a co-owner.
According to the law prevailing in some areas, a coparcener of a Hindu Joint Family can alienate his share in the Joint Family Property for consideration. Such a coparcener is a legally competent person. But in some cases of Mitakshara coparcenary, the consent of other coparceners is required before any such transfer.
Also, where one co-owner is in exclusive possession of a plot of a joint land and lets it out to a tenant without the consent of other co-sharer landlords, such a tenancy will not bind the latter. The lease in such a case will only be confined to the interest and share of the lessor.
In Baldev Singh v. Darshani Devi it was held by the Court that a co-owner who is not in actual physical possession over a parcel of land cannot transfer a valid title of that portion of the property. The remedy available to the transferee would be to get a share out from the property allotted after the partition or to get a decree for joint possession or can claim compensation from the co-owner.
In Rukmini and others v. H.N T. Chettiar it was held by the High Court of Madras that a co-sharer cannot be allowed to cause prejudice to the other co-sharers by putting up a substantial construction during the pendency of a suit for partition filed by the other co-sharers. The High Court of Punjab and Haryana in a case of Hazara Singh v. Faqiria where a co-owner contended that he had, by adverse possession, a peaceful undisturbed possession by the other co-owners had become the sole owner of a land, held that the possession of a co-owner is possession of all the co-owners. It cannot be adverse to them unless there is a denial of their right to knowledge by the person in possession. If a co-sharer is in possession of the entire property, his possession cannot be deemed to be adverse he possesses the property on behalf of all others.