Tax-Loss Harvesting: How Investors Turn Market Dips Into Tax Savings
Most investors wait for markets to go up. I’ve spent years also planning for when they go down — because a down market is an opportunity if you know how to use it. Tax-loss harvesting is one of the highest-leverage tax strategies available to investors in taxable accounts, and it costs you nothing in long-term returns when done correctly.
Let me show you exactly how it works.
The Core Concept
Tax-loss harvesting is the practice of selling an investment that has declined in value to realize a capital loss — and immediately reinvesting in a similar (but not identical) investment so you stay in the market. The loss you realized can offset capital gains elsewhere in your portfolio, or up to $3,000 of ordinary income per year. Any excess losses carry forward indefinitely.
You don’t exit the market. You don’t change your long-term allocation. You just capture a loss on paper that reduces your tax bill, then immediately buy back in with a similar fund.
A Real Example: $15,000 in Losses
Say you hold $100,000 in VOO ([Vanguard](https://investor.vanguard.com/?ref=aedilis) S&P 500 ETF) and the market drops 15%. Your position is now worth $85,000 — a paper loss of $15,000. You sell VOO and immediately buy VTI (Vanguard Total Stock Market ETF), which tracks a slightly different index but behaves almost identically to VOO.
You’re still fully invested in a near-identical US equity fund. But you’ve booked a $15,000 capital loss. If you have $15,000 in capital gains elsewhere that year (from selling rental property, a business stake, or other appreciated stocks), the loss eliminates the tax on those gains entirely. At a 15% long-term capital gains rate, that’s $2,250 in taxes avoided. At 20% + 3.8% NIIT, it’s $3,570.
The Wash-Sale Rule: The Critical Constraint
The IRS isn’t naive. They prohibit you from selling an investment for a loss and buying back a “substantially identical” security within 30 days before or after the sale. This is the wash-sale rule, and violating it disallows the loss.
Substantially identical generally means the same fund or stock. Selling VOO and buying back VOO 15 days later: wash sale. Selling VOO and buying VTI: not a wash sale (different index, different fund, similar but not identical exposure).
The Fund Pairs That Work
| Sell | Buy | Exposure |
|---|---|---|
| VOO (Vanguard S&P 500) | VTI (Vanguard Total Stock Market) | US Large Cap → US Total Market |
| SPY (SPDR S&P 500) | IVV (iShares S&P 500) | S&P 500 → S&P 500 (different provider) |
| VXUS (Vanguard International) | IXUS (iShares International) | International → International |
| BND (Vanguard Total Bond) | AGG (iShares Core Bond) | US Bonds → US Bonds |
The key is that the replacement fund tracks a different index or is issued by a different provider — similar enough to maintain your investment thesis, different enough to avoid wash-sale disallowance.
$3,000 Annual Ordinary Income Offset
Even if you have no capital gains to offset, tax-loss harvesting creates value. Up to $3,000 in net capital losses can offset ordinary income (your salary) each year. For someone in the 32% bracket, that’s $960 in tax savings annually, every single year they have harvestable losses. Carry-forward losses keep working year after year until they’re used up.
When to Harvest
I review my taxable portfolio for harvesting opportunities:
- During significant market corrections (5%+ drops in major indices)
- At year-end as part of annual tax planning
- After any large capital gain event (property sale, business exit, RSU vesting)
Sophisticated investors and robo-advisors ([Betterment](https://www.betterment.com/?ref=aedilis), Wealthfront) harvest continuously, scanning daily. For most people, quarterly reviews and opportunistic harvesting during corrections is sufficient.
The Long-Term Return Cost: Nearly Zero
The common objection: “Doesn’t selling reset my cost basis lower, so I’ll owe more taxes when I eventually sell?” Yes — but only if you sell eventually at a gain. Many investors hold their replacement funds until death, at which point heirs receive a step-up in cost basis and the deferred gain disappears entirely. Or you can continue to harvest losses in future downturns, perpetually deferring the gain.
Empirically, studies suggest systematic tax-loss harvesting adds 0.5–1.5% in annual after-tax returns with no change in pre-tax returns. That’s not trivial compounded over 20–30 years.
What It Won’t Do
Tax-loss harvesting works in taxable brokerage accounts only. It provides no benefit in IRAs or 401(k)s (no tax event on sales within those accounts). And it requires that you actually have unrealized losses — in a steadily rising market year, there may be nothing to harvest. That’s fine. The strategy works across a full market cycle, not every individual year.
The market will have bad days. Bad months. Sometimes bad years. I’ve trained myself to see those moments not as losses but as harvesting opportunities. The tax code gives you a tool to turn paper losses into real, permanent tax savings. Use it.