Bitcoin and many other cryptocurrencies have currency-caps implemented in their protocols, compiled by consenting operators. Bitcoin, for example, is capped at approximately 21 million bitcoins. 

This paper discusses whether such currency-caps are illegal quantity-fixing conspiracies in violation of antitrust law. It is found that there is a present antitrust risk for cryptocurrency operators. This may render such operators subject to criminal and civil liabilities.

To determine whether currency-caps are antitrust conspiracies, we consider cryptocurrencies as money, securities and commodities and answer the following questions:  

• Are the operators liable entities?
• Do they behave unilaterally or in coordination?
• Are the operators a company or a structural joint venture?
• Do currency-caps restrict trade?
• Do they have legitimate justifications?