He served as a public director on the Chicago Board of Trade 1983–85 and the Chicago Mercantile Exchange from 1990 until his death in Chicago on June 3, 2000. In 1993, Miller waded into the controversy surrounding $2 billion in trading losses by what was characterized as a rogue futures trader at a subsidiary of Metallgesellschaft, arguing in the "Wall Street Journal" that management of the subsidiary was to blame for panicking and liquidating the position too early. In 1995, Miller was engaged by Nasdaq to rebut allegations of price fixing.