If you want to know when to sell an investment, start by writing why you bought it. A buy reason turns a future sell decision from a price-driven reaction into a review of the original thesis: the job the position was hired to do, the evidence that supported it, and the condition that would make that reason false.
As of 2026-04-23, fund costs and tax references below are summarized from issuer and IRS sources listed at the end. This article is educational, not tax, legal, or investment advice; verify current rules and consult a qualified professional for your situation.
This framework is not personalized investment advice. Use Deep Digital Ventures Portfolio Tracker to record buy reasons, thesis notes, position size, and review triggers at purchase, so a later sell review starts from the original evidence instead of the best story you can remember after the price has moved.
Quick answer: A buy reason is a short investment thesis written before hindsight gets involved. The fields that matter most are position job, source checked, key metric, maximum size, and sell or trim trigger. The value is simple: when the position moves, you compare today’s facts with the original reason instead of deciding from discomfort, excitement, or tax-season pressure.
What is a buy reason?
A useful buy reason is specific enough to be falsified later. ‘Good company’ does not define evidence. ‘Dividend-equity sleeve because the fund follows a dividend-quality index, the current issuer expense ratio is below my 0.10% ceiling, and I will review if the index objective changes’ is reviewable.
Issuer pages are the right source for fund details when the thesis depends on cost, objective, or holdings. The Schwab Asset Management page for SCHD lists a 0.060% total expense ratio, the iShares page for AGG lists a 0.03% prospectus expense ratio, and Vanguard’s VOO fund profile should be checked for VOO’s current objective, holdings, and cost before the note is updated.[1][2][3]
Cost-sensitive ETF theses should name a limit, not just say ‘low cost.’ Vanguard’s ETF fees page reports a Vanguard average ETF expense ratio of 0.04% and an industry average ETF expense ratio of 0.23%, using Vanguard and Morningstar data dated December 31, 2025, so a ‘low-cost core’ thesis should record the fund’s current expense ratio and the maximum ratio that would force a review.[4]
What investors usually get wrong
The common failure is not lack of data. It is changing the question after the price moves. A stock bought for income gets judged like a growth stock. A bond ETF bought as ballast gets criticized for not behaving like an equity fund. An overweight winner gets defended with a new story that was not written down at purchase.
That is one pattern the tracker is built to solve. It keeps the original job, source, size, and trigger next to the position, so the sell review starts with the evidence that existed when you made the decision. If today’s reason is different from the original reason, write it as a dated thesis change instead of pretending it was always the plan.
What should a buy note include?
The master note should be short enough to maintain and specific enough to audit. The table below is the core framework; use it for ETFs, dividend stocks, bond funds, cash substitutes, and single-company positions.
| Field | What to write | How it helps the sell review |
|---|---|---|
| Position job | U.S. large-cap index sleeve, dividend-income sleeve, bond ballast, cash substitute, or single-company thesis | Prevents comparing VOO to AGG or a dividend stock to a money-market substitute |
| Source at purchase | Issuer fund page, SEC filing, dividend notice, broker confirmation, or written allocation plan | Shows which source should be checked before selling |
| Time horizon | Example: 3 years for a business recovery, 12 months for a valuation reset, indefinite for a core allocation sleeve | Prevents judging a long-term position by one bad month |
| Key metrics | ETF expense ratio, index objective, holdings drift, revenue, free cash flow, debt, payout ratio | Turns the sell decision into evidence review |
| Main risk | The condition that would prove the thesis wrong, such as dividend cut, leverage spike, index change, or loss of income role | Separates bad news from noise |
| Position size | Target weight and maximum intended weight, such as target 6% and review at 8% | Connects conviction to portfolio risk |
| Review trigger | Quarterly statement, annual report, dividend announcement, ETF methodology change, or calendar date before year-end | Makes review scheduled instead of emotional |
How do sell triggers work?
The best time to define a sell trigger is before a price move makes the position feel personal. A sell trigger does not have to be automatic. It should say what evidence forces a review, how fast you will review it, and whether the likely action is hold, trim, sell, or replace.
- Income thesis: review within 7 days if the dividend is cut, suspended, or no longer covered by free cash flow for two annual reports.
- Balance sheet thesis: review if net debt to EBITDA moves above the ceiling written in the note, such as 3.0x.
- ETF thesis: review if the issuer changes the benchmark, the expense ratio moves above your stated limit, or the holdings no longer match the sleeve.
- Position-size thesis: trim review if a 6% target position reaches 8% of the portfolio without a fresh written reason.
- Replacement thesis: compare the current holding to the named replacement only on the original job, such as bond ballast, dividend income, or U.S. large-cap exposure.
The table below uses one hypothetical position-size review. It is not a recommendation to buy, sell, or hold SCHD; it shows how the note turns a vague feeling into a repeatable check.
| Step | Worked example |
|---|---|
| Original buy note | SCHD is the dividend-equity sleeve; target weight 6%; review if weight reaches 8%, expense ratio exceeds 0.10%, or the fund no longer tracks a dividend-quality index. |
| Review date facts | Total portfolio is $850,000; SCHD value is $76,500; current weight is 9.0%. |
| Decision math | $850,000 portfolio x 6% target = $51,000 target value; actual SCHD value is $76,500; possible trim amount is $25,500 before commissions, bid/ask spread, and tax-lot review. |
| Evidence result | Thesis intact, position-size trigger fired, no automatic full sale needed. |
| Action note | Trim only enough to return to target unless a new written allocation reason supports a higher weight. |
Taxable-account considerations
For taxable brokerage accounts, add tax lot method, holding period, and covered or noncovered basis status to the note. IRS Publication 550 describes covered securities as subject to added reporting by brokers on Form 1099-B, and IRS Publication 551 explains basis as the investment amount used to figure gain or loss.[5][6][7] For a deeper recordkeeping workflow, see the separate guides on tax lots and cost basis, the wash-sale rule, and qualified dividends.
Dividend-income investors should record whether the thesis depends on qualified dividend treatment, because IRS Publication 550 says common stock generally must be held for more than 60 days during the 121-day period that begins 60 days before the ex-dividend date, and Form 1099-DIV reports dividends and distributions.[5][8]
For a taxable-account loss sale, add a separate trigger: "Do not rebuy substantially identical stock or securities inside the 30 days before or 30 days after the sale unless I have reviewed wash-sale treatment across taxable, IRA, Roth IRA, spouse, and controlled-entity accounts." IRS Publication 550 says wash sales can occur when a taxpayer sells stock or securities at a loss and buys substantially identical stock or securities within 30 days before or after the sale.[5]
If a sale creates a net capital loss, IRS Publication 550 says the capital loss deduction figured on Schedule D is limited to the lesser of $3,000, or $1,500 if married filing separately, or the total net loss shown on Schedule D line 16, with unused losses potentially carried forward.[5]
At year-end, the sell note should also preserve records needed to reconcile broker reporting. Form 8949 reconciles amounts reported to you and the IRS on Form 1099-B or Form 1099-S with amounts reported on your return, and Schedule D aggregates capital gains and losses.[9][10] Tax reminder: this section is only a checklist for what to capture before you talk with a qualified tax professional.
Separate thesis failure from price movement
A falling price does not always mean the thesis failed, and a rising price does not always mean the thesis worked. A 20% price decline after a broad market selloff is different from a dividend suspension, a covenant breach, a surprise index change, or a fund expense increase above the ceiling you wrote down.
At each review, answer the same questions in the same order:
- What did I expect? Name the original claim, such as revenue recovery, dividend growth, bond ballast, or low-cost index exposure.
- What actually happened? Use the issuer page, SEC filing, dividend announcement, fund page, or broker statement named in the buy note.
- Does the evidence support, delay, or break the thesis? Choose one word first, then explain it in one or two sentences.
- Is the position size still appropriate? Divide current market value by total portfolio value, then compare it with the target and maximum written in the note.
- Is this a sell, trim, hold, or replace review? Do not let ‘I am uncomfortable’ stand in for evidence.
Buy-reason template
Use this template when opening or reviewing a position. Short answers are fine, but blank fields should be intentional.
Position:
Account type:
Date:
Source checked:
Position job:
Buy reason:
Expected time horizon:
Key metrics to watch:
Main risks:
Tax lot and basis note if taxable:
Maximum intended position size:
Review cadence:
Review trigger:
Sell or trim trigger:
Replacement rule:
Next review date:
FAQ
Should every holding have a written buy reason?
Yes. A one-line reason is enough for a small ETF sleeve, but every holding should still have a job, a maximum size, and one condition that would force review.
Can the buy reason change?
It can evolve, but the change should be dated. If the reason changes every time the price moves against you, treat that as thesis drift and run a full sell review.
What if I do not remember the original reason?
Write a reconstruction note and label it as reconstructed. Then set a fresh review trigger based on evidence you can verify today, such as issuer objective, current position weight, fund cost, dividend policy, or debt level.
Sources
- Schwab Asset Management SCHD fund page: https://www.schwabassetmanagement.com/products/schd
- iShares AGG fund page: https://www.ishares.com/us/products/239458/ishares-core-total-us-bond-market-etf
- Vanguard VOO fund profile: https://investor.vanguard.com/investment-products/etfs/profile/voo
- Vanguard ETF fees page: https://investor.vanguard.com/investment-products/etfs
- IRS Publication 550, Investment Income and Expenses: https://www.irs.gov/publications/p550
- IRS Publication 551, Basis of Assets: https://www.irs.gov/publications/p551
- IRS Form 1099-B information page: https://www.irs.gov/forms-pubs/about-form-1099-b
- IRS Form 1099-DIV information page: https://www.irs.gov/Form1099DIV
- IRS Form 8949 information page: https://www.irs.gov/forms-pubs/about-form-8949
- IRS Schedule D information page: https://www.irs.gov/forms-pubs/about-schedule-d-form-1040