Career
Siegel held his first philatelic auction in Kansas City, Missouri. In 1934 he moved his philatelic auction business to New York City and eventually conducted 756 philatelic auctions during his lifetime. In 1964 he conducted his first Rarity Sale.
Subsequent Rarity Sale auctions sold world-famous classic postage stamps, including selling—on two different occasions—the unique British Guiana one cent on magenta, for record prices.
Siegel remained active in the American Stamp Dealers Association and served on its board for twelve years. As an expert on rarities, Siegel supported the Philatelic Foundation with his advice and support.