Ind. Code § 24-1-2-1

Sec. 1. Every scheme, contract, or combination in restraint of trade or commerce, or to create or carry out restrictions in trade or commerce, or to deny or refuse to any person participation, on equal terms with others, in any telegraphic service transmitting matter prepared or intended for public use, or to limit or reduce the production, or increase or reduce the price of merchandise or any commodity, or to prevent competition in manufacturing, within or without this state, is illegal, but this chapter may not be construed to apply to or repeal, modify or limit, or make unlawful any of the powers, rights or privileges now existing or conferred by law upon any person. A person who makes such a contract, engages in such a combination, or enters into such a scheme, or does within this state any act in furtherance of such a contract, combination, or scheme entered into without this state, commits a Class A misdemeanor. However, it is a defense to any action growing out of any violation of any law relating to the subject-matter of this chapter for the defendant to prove that the violation is not in restraint of trade or commerce, or does not restrict trade or commerce, limit or reduce the production, or increase or reduce the price of merchandise or any commodity, or prevent competition in manufacturing.