2026 is the first full year under the One Big Beautiful Bill Act (OBBBA), and traders have plenty to think about before the closing bell on December 31. The core trader tax rules haven't changed: trader tax status (TTS), the Section 475 mark-to-market election, and the 60/40 treatment for Section 1256 contracts all still apply. What has changed is how loss limits, the QBI deduction, the SALT cap, and retirement planning fit together. If you plan now, you can save real money. If you wait until April, most of these moves will be gone. Here's my year-end roadmap for traders in equities, options, futures, and crypto. This is Part 1 of a two-part series. Part 2 covers year-end planning for trading entities: S-corps, LLCs, officer compensation, health insurance, Solo 401(k)s, and the PTET workaround for the SALT cap. This playbook covers federal tax rules. States often don't follow federal rules...