Joint venture classification determines tax assessment; combined enterprises producing income may be assessed as firms under tax law. Whether transactions by two or more persons constitute a joint venture depends on case facts and Supreme Court precedent; prior circulars are withdrawn. If persons combined in a joint enterprise to produce income, the combination is a joint venture whose tax treatment follows its legal character: a joint venture not meeting firm requisites is to be assessed as a firm, and a joint venture that is a firm will be assessed under the applicable income tax provisions. Assessing officers must be notified.