The Statute
The IRS provides for exemption of business leagues, chambers of commerce, real estate boards and boards of trade which are not organized for profit and no part of the net earnings of which inures to the benefit of any private shareholder or individual.
Regulations
A business league is defined as an association of persons having a common business interest, whose purpose is to promote the common business interest and not to engage in a regular business of a kind ordinarily carried on for profit. Its activities are directed to the improvement of business conditions of one or more lines of business rather than the performance of particular services for individual persons.