Year-End Tax Loss Harvesting Checklist (2026): Capture Losses Without Wash Sales

Tax loss harvesting can reduce your tax bill, but only if you avoid wash sales and track cost basis correctly. Use this checklist each year before you file.

For the full rulebook and edge cases, review the Wash Sale Rules Complete Guide.

Step 1: Identify Realized Gains So Far

Start with your realized gains and losses. If you do not know your totals, use the Capital Gains Tax Optimizer or your brokerage tax summary to get a clear view.

Step 2: Flag Loss Positions Worth Harvesting

Look for positions with meaningful unrealized losses that align with your investment plan. Selling just for tax reasons can be counterproductive if you do not have a replacement plan.

Step 3: Check the 30-Day Window

The wash sale rule looks 30 days before and after your sale. Any purchase of the same or substantially identical security in that window can disallow your loss.

Use our free wash sale calculator to calculate the 61-day wash sale window and confirm no violations before you sell. The calculator tracks FIFO, LIFO, and specific lot methods to match your broker.

Step 4: Pick Replacement Positions Carefully

If you want to stay invested, replace the position with a similar but not substantially identical security. This keeps exposure while avoiding wash sales.

Step 5: Watch for RSU Vesting and ESPP Purchases

RSU vesting counts as a purchase and can trigger a wash sale if it happens inside the 30-day window. If you receive equity compensation, read How to Avoid Wash Sales with RSUs.

Step 6: Track Cost Basis Changes

If you trigger a wash sale, your cost basis adjusts. Keep those records clean so you do not double-count income later. The basics are covered in RSU Cost Basis and Capital Gains.

Step 7: Estimate the Tax Impact

Use the Tax Calculator to estimate how harvested losses affect your overall tax bill.

Related Tools and Guides

• Tax Loss Harvesting Calculator
• Wash Sale Calculator - Free calculator to detect IRS wash sales and calculate cost basis adjustments
• Capital Gains Tax Optimizer
• Estimated Tax Payments Guide

A clean year-end checklist saves hours at filing time and keeps your losses usable instead of disallowed.