Solo 401(k) vs. SEP IRA: Which Retirement Plan Saves High-Income Freelancers the Most Tax? October 9, 2025 by Ethan Cole Finance & Income Strategies Solo 401(k) vs. SEP IRA: Which Retirement Plan Saves High-Income Freelancers the Most Tax? Introduction: The High-Earner’s Tax Challenge If you are a high-income freelancer, independent contractor, or small b ...