This invention provides a process for producing a protic ammonium tetrakis(Faryl)borate. The process comprises mixing together (a) at least one alkali metal tetrakis(Faryl)borate, at least one magnesium tetrakis(Faryl)borate, at least one halo-magnesium tetrakis(Faryl)borate, or a mixture of two or more of the foregoing, (b) at least one amine, and (c) one or more liquid dihydrocarbyl ethers, one or more liquid hydrocarbons, one or more liquid halogenated hydrocarbons, or a mixture of two or more of the foregoing, to form a solution or slurry in a liquid organic medium. At least one protic acid is mixed together with at least a portion of the solution or slurry formed in i), such that a protic ammonium tetrakis(Faryl)borate is formed. The amine has the formula R3N, in which each R is independently a hydrocarbyl group containing up to about thirty carbon atoms. Each of the Faryl groups is a fluorine-containing aryl group that has bonded directly to an aromatic ring at least two fluorine atoms, or at least two perfluorohydrocarbyl groups, or at least one fluorine atom and at least one perfluorohydrocarbyl group.