Selling a stock at a loss lets you offset capital gains and deduct up to $3,000 per year against your ordinary income. Called tax-loss harvesting, it’s one of the most powerful (and legal) tax strategies available to investors.

How Capital Losses Work

Step What Happens
1 You sell a stock for less than you paid
2 The difference is a capital loss
3 Short-term losses (held < 1 year) offset short-term gains first
4 Long-term losses (held > 1 year) offset long-term gains first
5 Net losses offset gains from the other category
6 Remaining net losses deduct up to $3,000 against ordinary income
7 Excess losses carry forward to future years

Tax Savings Examples

$10,000 loss, 24% tax bracket:

Scenario How the Loss Is Used Tax Savings
$10,000 in gains to offset Loss offsets all gains $1,500-$2,400 (depending on gain type)
$5,000 in gains + $3,000 ordinary income offset Loss offsets gains + $3K income $1,470
No gains at all $3,000 offset/year for 3.3 years $2,400 total (spread over years)

Detailed breakdown with $15,000 long-term loss, $8,000 long-term gain, 24% bracket:

Item Amount
Long-term capital loss -$15,000
Long-term capital gain +$8,000
Net capital loss -$7,000
Year 1: Offset ordinary income -$3,000 (saves $720)
Year 2: Carry forward to offset income -$3,000 (saves $720)
Year 3: Remaining carry forward -$1,000 (saves $240)
Total tax savings $1,680

Short-Term vs. Long-Term Losses

Loss Type Holding Period First Offsets Tax Rate on Offset Gains
Short-term loss Under 1 year Short-term gains Up to 37% (ordinary rates)
Long-term loss Over 1 year Long-term gains 0-20% (LTCG rates)

Short-term losses are more valuable because they first offset gains taxed at higher ordinary income rates.

The Wash Sale Rule

Rule Details
What it is You can’t claim a loss if you buy the same/substantially identical security within 30 days
Window 30 days before AND 30 days after the sale (61-day total window)
What triggers it Buying the same stock, substantially identical stock, option on same stock
What happens Loss is disallowed; added to new shares’ cost basis
Applies to All accounts you own (taxable, IRA, spouse’s accounts)

What counts as “substantially identical”:

Substantially Identical? Example
✅ Yes Selling Apple stock, buying Apple stock within 30 days
✅ Yes Selling shares, buying call options on same stock
❌ No Selling S&P 500 index fund (Vanguard), buying S&P 500 ETF (iShares) — debatable
❌ No Selling one tech stock, buying a different tech stock
❌ No Selling individual stock, buying a broad market index fund

Tax-Loss Harvesting Strategy

Step Action
1 Identify losing positions in your taxable account
2 Sell the losing position
3 Immediately buy a similar (but not substantially identical) investment
4 Wait 31 days if you want to buy back the exact same security
5 Claim the loss on your tax return (Schedule D)

Example swap pairs (not substantially identical):

Sell Buy Instead
Vanguard Total Stock Market (VTI) Schwab Broad Market ETF (SCHB)
S&P 500 index fund Total Market index fund
Individual tech stock Technology sector ETF

Reporting on Your Tax Return

Form Purpose
Form 8949 Report each sale: date bought, date sold, proceeds, cost basis, gain/loss
Schedule D Summary of all gains and losses; calculate net gain or loss
Line 7 of Schedule 1 Carry the net loss (up to $3,000) to your 1040
Capital Loss Carryover Worksheet Track unused losses for future years

The Bottom Line

Selling a stock at a loss isn’t just losing money — it’s creating a tax asset. Use losses to offset gains, deduct up to $3,000/year against income, and carry forward the rest. Just avoid wash sales (wait 31 days or buy something similar but not identical). Tax-loss harvesting is one of the easiest ways to improve your after-tax returns without changing your investment strategy.

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