Tax-Loss Harvesting Explained: How to Turn Market Dips into Permanent Tax Alpha

Turning Volatility into Guaranteed Tax Savings

In a taxable brokerage account, market corrections offer a silver lining: the opportunity to harvest unrealized losses to reduce your IRS tax bill without ever leaving the market. Tax-Loss Harvesting (TLH) is the practice of selling an ETF or stock that is trading below your purchase price (cost basis), realizing the capital loss for tax purposes, and immediately reinvesting the proceeds into a similar (but not "substantially identical") ETF to maintain your exact market exposure.

How the IRS Applies Harvested Losses

1. Step 1: Offset Capital Gains Dollar-for-Dollar (Unlimited): Realized losses first offset any short-term capital gains (which are otherwise taxed at ordinary income rates up to 37% + 3.8% NIIT) and long-term capital gains (taxed at 15%–20% + 3.8% NIIT). There is no dollar cap on how much capital gain you can offset.
2. Step 2: Deduct Up to $3,000 Against Ordinary W-2 / Business Income: If your harvested losses exceed your capital gains for the year, you can deduct up to $3,000 ($1,500 if married filing separately) directly against your ordinary taxable income.
3. Step 3: Infinite Tax-Loss Carryforward: Any remaining net capital loss above $3,000 carries forward indefinitely to future tax years until fully utilized.

Navigating the IRS 61-Day Wash-Sale Rule (IRC Section 1091)

To prevent investors from selling a security at 10:00 AM solely for the tax deduction and buying the exact same ticker back at 10:01 AM, the IRS enforces the Wash-Sale Rule.

A wash sale occurs if you (or your spouse, or an IRA/401(k) you control) buy a "substantially identical" security within 30 calendar days before or 30 calendar days after the sale date (a 61-day total window, including the day of sale).

How to Harvest Losses Without Triggering a Wash Sale:

Swap between ETFs that track different underlying index providers while maintaining 99% correlation:

• US Large-Cap Blend Swap: Sell Vanguard S&P 500 ETF (VOO, tracks S&P 500 Index) → Buy Schwab US Large-Cap ETF (SCHX, tracks Dow Jones US Large-Cap Total Stock Market Index) or Vanguard Total Stock Market ETF (VTI, tracks CRSP US Total Market Index).
• International Developed Swap: Sell Vanguard FTSE Developed Markets ETF (VEA, tracks FTSE index) → Buy iShares Core MSCI EAFE ETF (IEFA, tracks MSCI index).

Because FTSE, MSCI, CRSP, and S&P are distinct index methodologies with different constituent counts, swapping between them keeps 100% of your capital invested in the market on the same day while locking in your tax deduction.