The Generation Skipping Transfer Tax1 does not apply to generation-skipping transfers under a trust that was irrevocable on September 25, 1985.2 That rule is clear and any trust existing on September 25, 1985 is considered to be an irrevocable trust unless otherwise provided.3 However, there are several exceptions that can snare irrevocable trusts in existence on September 25, 1985 and subject transfers to GSTT. A few of the major problem areas are discussed below.