applicable partnership interest
(1) In general Except as provided in this paragraph or paragraph (4), the term “applicable partnership interest” means any interest in a partnership which, directly or indirectly, is transferred to (or is held by) the taxpayer in connection with the performance of substantial services by the taxpayer, or any other related person, in any applicable trade or business. The previous sentence shall not apply to an interest held by a person who is employed by another entity that is conducting a trade or business (other than an applicable trade or business) and only provides services to such other entity.