Tax-loss harvesting uses a realized investment loss to offset capital gains. The wash sale rule can postpone that deduction, or remove it. Sell at a loss, then buy a substantially identical investment too soon, and the loss may not show up on the return you expected. Timing, the replacement, and who owns the account all matter. The ticker alone does not.
Talk with Great Point before you sell at a loss.
This is a tax-loss harvesting strategy explained from the trade outward. It covers how a loss can reduce a capital-gains bill, why short-term and long-term holding periods are netted apart, and how the 61-day wash-sale window, basis, and an IRA purchase can change the result. For the wider planning context, see Great Point’s tax and estate planning overview.
Tax-loss harvesting strategy explained
Tax-loss harvesting is the deliberate sale of an investment that has declined in value. The sale realizes a capital loss that may offset realized capital gains, subject to the capital-loss rules and the investor’s tax situation. An investor may then choose a replacement investment to maintain a desired level of market exposure.
The wash sale rule limits that strategy when the replacement is substantially identical. Internal Revenue Code section 1091 disallows the loss if you acquire substantially identical stock or securities too close to the sale. The IRS explains the same rule in Publication 550, Investment Income and Expenses.
Key idea: Selling at a loss is not enough to create a currently usable tax loss. The purchases surrounding the sale must also be reviewed.
The rule does not generally prohibit an investor from buying the investment again. Instead, it changes when the loss can be recognized. In a taxable account, the disallowed loss is usually added to the basis of the replacement shares. That postpones the tax result rather than making the loss disappear, although an IRA replacement can produce a harsher result.
How harvested losses can offset capital gains
A tax-loss harvesting strategy starts with gains and losses in a taxable portfolio. A short-term loss offsets short-term gains first. A long-term loss offsets long-term gains first. A leftover loss in one group can then offset a gain in the other, under the Schedule D rules.
After that netting, Publication 550 limits the capital loss deduction. It is the lesser of $3,000 ($1,500 if married filing separately) or your total net loss on Schedule D. Unused losses carry forward. The cap depends on the full return, not on one sale.
Here is a simple case. You sell one taxable holding at a $9,000 long-term loss and another at a $6,000 long-term gain. Before other trades, the loss covers the gain and leaves a $3,000 net long-term loss. You still need to ask whether the sales fit the portfolio, whether a replacement washes the loss, and how the trades will be reported.
Loss harvesting is not automatically beneficial. A sale can change the portfolio’s risk, expose an investor to a different holding period, create trading costs, or conflict with a rebalancing plan. A lower current tax bill is one input, not the entire investment decision. Great Point’s guide to capital gains tax for investors provides additional context for the tax side of investment decisions.
Short-term versus long-term gains
The holding period affects how a realized capital gain or loss is classified. In general, an investment held for one year or less produces a short-term gain or loss. An investment held for more than one year produces a long-term gain or loss. The exact holding-period calculation can be affected by the type of security, acquisition history, and special tax rules.
Short-term gains are generally taxed at ordinary income tax rates, while long-term gains may qualify for preferential federal rates. That difference is why a tax-loss harvesting strategy should consider which gains a loss may offset, not only the dollar amount of the loss.
A wash sale can also change the replacement lot’s holding period. Publication 550 adds the old holding period to the new shares when the loss is disallowed and folded into basis. That carryover matters when you later sell the replacement.
Do not confuse tax timing with investment performance. A harvested loss may improve the timing of a tax result, but it does not turn a losing investment into a profitable one. The replacement security still needs to make sense for the portfolio.
What the 61-day wash sale window covers
The wash sale window runs 30 days before the loss sale and 30 days after it. Count the sale date in the middle and the window is 61 days. A purchase on day 30 is inside. A purchase on day 31 is outside, if no other buy falls in the window.
A wash sale can occur when, within that window, the investor does any of the following:
- Buys substantially identical stock or securities.
- Acquires substantially identical stock or securities in a fully taxable trade.
- Acquires a contract or option to buy substantially identical stock or securities.
- Acquires substantially identical stock for an IRA or Roth IRA.
The purchase does not need to happen in the same brokerage account as the sale. A spouse’s purchase can count. A purchase by a corporation the investor controls can also count. A dividend reinvestment, automatic contribution, or recurring investment may be easy to overlook, so the review should include all relevant accounts.
The rule is generally applied to matched shares when the number of replacement shares differs from the number sold. Suppose an investor sells 100 shares at a loss and buys 60 substantially identical shares within the window. The loss on the 60 matched shares may be disallowed. The other 40 shares may still keep their loss, subject to the facts and the reporting rules.
What substantially identical means
Substantially identical is a facts-and-circumstances test. Stock of one corporation is ordinarily not substantially identical to stock of another corporation, but a reorganization or a predecessor-successor relationship can change the analysis. A corporation’s common stock is not ordinarily substantially identical to its bonds or preferred stock, although convertible preferred stock can require a closer review.
Two exchange-traded funds may track similar markets without automatically being substantially identical, but similarity alone does not settle the question. An investor should not rely on a fund name or a ticker symbol alone. The security’s legal and economic features matter.
Options and other contracts deserve particular caution. An option to buy the same stock can fall within the rule even though the investor did not purchase additional shares. When the proposed replacement is complex, a tax professional should review the facts before the trade.
How a disallowed loss changes cost basis
In a taxable account, add the disallowed loss to the cost of the new shares. That total is your basis. The loss waits until you sell those shares. The original sale does not produce a deduction this year.
Here is a simple example:
- An investor buys 100 shares for $1,000.
- The investor sells those shares for $750, creating a $250 loss.
- Within the wash sale window, the investor buys 100 substantially identical shares for $800.
- The $250 loss is disallowed for the original sale.
- The basis of the replacement shares becomes $1,050, or $800 plus the $250 disallowed loss.
If you later sell the replacement shares for $1,200, measure the gain or loss from the adjusted basis. Other rules can still apply. If only some replacement shares match the sale, allocate the disallowed loss to those matched shares.
Brokerage statements may identify wash sales, but a broker may not see a spouse’s account, an account at another firm, or every IRA transaction. The taxpayer remains responsible for the complete picture. Keep trade confirmations, account statements, and records of automatic purchases.
| Situation | Likely tax treatment | Planning question |
|---|---|---|
| Loss sale with no substantially identical purchase in the 61-day window | The loss may be available, subject to other tax rules. | What gains or future income could the loss offset? |
| Taxable-account purchase of matched replacement shares | The matched loss is generally disallowed and added to replacement basis. | When will the replacement lot be sold, and are records complete? |
| Fewer replacement shares than shares sold | Only the matched portion is generally washed. | Which lots and share counts match? |
| Spouse or controlled corporation buys substantially identical shares | The loss may be disallowed even though the investor’s account did not make the purchase. | Have all related accounts been checked? |
| IRA or Roth IRA buys substantially identical shares | The loss is disallowed, and IRA basis is generally not increased by the loss. | Could an automatic contribution or reinvestment create an irreversible result? |
The IRA wash sale trap
Buying the same shares in an IRA or Roth IRA after a taxable loss sale needs a separate look. Revenue Ruling 2008-5 disallows the loss. It also says IRA or Roth IRA basis is not increased under the wash sale rule.
That differs from the usual taxable-account result. In a taxable account, the disallowed loss generally moves into the basis of the replacement shares. In an IRA, there may be no corresponding taxable basis adjustment to preserve the loss. For that reason, a retirement-account contribution, dividend reinvestment, or automatic purchase can be especially important to identify before harvesting a loss.
This is not a reason to avoid retirement contributions or to change an investment plan without advice. It is a reason to coordinate account activity before placing a loss sale. The tax consequences can depend on the security, the accounts involved, and the timing.
A practical review before harvesting a loss
A useful review begins before the trade, not when the annual tax documents arrive. Use the following checklist as a starting point, then ask a qualified tax professional to confirm the reporting.
- Identify the proposed loss. Record the security, lot, purchase date, cost basis, expected sale date, and number of shares.
- Separate short-term and long-term lots. Note which gains or losses the sale could affect and whether selling the lot changes the portfolio’s intended exposure.
- Search backward 30 days. Review purchases, reinvestments, options, and contracts in taxable accounts, spouse accounts, and retirement accounts.
- Plan forward 30 days. Pause or account for automatic investments, dividend reinvestment, recurring purchases, and planned IRA or Roth IRA transactions.
- Evaluate the replacement. If market exposure is important, consider whether a replacement is sufficiently different. Do not assume two securities are different merely because their names differ.
- Match share counts and lots. If the replacement is smaller than the sale, determine which shares are matched and how the disallowed loss is allocated.
- Save the evidence. Keep confirmations and statements from every relevant account, including accounts held at another institution.
- Review the tax return reporting. Compare broker-reported wash sales with the complete household transaction history before filing.
A tax-loss harvesting strategy should serve the investment plan. If the replacement changes diversification, risk, liquidity, or the desired holding period, the tax benefit may not justify the trade. Great Point’s Massachusetts tax-efficient investing guide offers another perspective on coordinating investment choices with tax considerations.
How an advisor can coordinate the moving pieces
The wash sale rule is one constraint inside a broader planning decision. The loss sale, replacement security, account type, holding period, realized gains, and future cash needs all fit together. An advisor can help organize the investment side of that review, while a qualified tax professional determines the tax treatment and filing position.
Great Point Wealth Advisors is an SEC-registered investment advisor in Boston. The firm can help clients coordinate investment decisions with tax-aware planning, but it does not replace a tax preparer or provide tax or legal advice. Families connecting investment taxes to gifts, trusts, or a future transfer can also review the firm’s estate planning and wealth transfer guide.
Contact Great Point Wealth Advisors to coordinate your tax-aware investment decisions.
Frequently Asked Questions
Does the wash sale rule ban me from buying the stock again?
No. You may buy the stock again. The rule can disallow the loss deduction if the purchase falls inside the 30 days before or after the sale and the shares are substantially identical. In a taxable account, the disallowed loss is generally added to the basis of the replacement shares.
How long is the wash sale window?
The window covers 30 days before the loss sale, the sale date, and 30 days after it. Together, that is 61 calendar days. A purchase on day 30 after the sale is inside the window; day 31 is outside it on those facts.
Can tax-loss harvesting offset short-term gains?
Generally, realized losses are netted with gains under the applicable capital-loss rules. Short-term losses generally offset short-term gains first, and long-term losses generally offset long-term gains first. The complete tax result depends on all of the taxpayer’s transactions and circumstances.
What if my IRA buys the shares I sold at a loss?
Revenue Ruling 2008-5 says the loss is disallowed. It also says the basis in the IRA or Roth IRA is not increased by the disallowed loss. That can be less favorable than a repurchase in a taxable account, where the loss is generally preserved in the new basis.
Will my broker catch every wash sale?
Not always. A broker can see trades in the accounts it holds, but it may not see a spouse’s account at another firm, an IRA held elsewhere, or every related transaction. The investor is responsible for reviewing the broader household picture.
Important Disclosure
This article is for general educational purposes only. It is not individualized investment, tax, or legal advice, and it is not a solicitation to buy or sell any security. Tax rules, including the wash sale rule, depend on your facts and can change. Great Point Wealth Advisors, LLC is a registered investment advisor. The firm does not provide tax or legal advice. Consult a qualified tax professional before you sell or replace an investment. All investments involve risk, including possible loss of principal. Past performance is not a guarantee of future results. Additional information about the firm is on the disclosures page.
Sources: IRS Publication 550 (2025), including wash sales and the capital loss limit. IRS Topic No. 409, Capital gains and losses. IRS Revenue Ruling 2008-5. Cornell Law School, 26 U.S.C. section 1091. Accessed October 20, 2026.