Discussion topic: Based on your chapter reading, key point lecture notes, and study ppt slides, please state that the major difference in the accounting for a portfolio of "trading securities" vs. "available-for-sale securities" vs. "held-to-maturity"? In other words, what are the main differences in accounting treatment among the three categorized investment holdings, trading securities, available-for-sale securities, and held-to-maturity (the accounting treatment rules, rationale behind, or underlying principle? (Do these rationales make sense to you?)