The purchase price (or purchase cost) is the price you pay to acquire an investment. That amount becomes the investment’s cost basis for calculating gain or loss when you later sell. The purchase price includes the market price plus any transaction costs you paid to buy the position (commissions, sales loads, transfer fees, etc.). Accurate purchase-price records are essential for computing realized gains/losses and for tax reporting.
Key points at a glance
– Purchase price = market price paid per share × number of shares, plus purchase commissions and fees.
– Cost basis determines realized gain or loss on sale: realized gain/loss = sale proceeds − cost basis.
– “Unrealized” gain or loss exists while you still hold the security; it is not taxed until realized (sold).
– When you have multiple purchases, you must use an accounting method (weighted average, FIFO, specific identification, etc.) to determine cost basis for shares sold. Brokerage firms report basis on Form 1099‑B and often let you select a method.
– Tax reporting: realized capital gains/losses are reported on Schedule D (and Form 8949) of IRS Form 1040.
Understanding realized vs. unrealized gains
– Unrealized gain (or loss): the market value of a holding is higher (or lower) than your cost basis, but you haven’t sold. No tax consequence until you sell.
– Realized gain (or loss): you sold the investment. Gain or loss equals sale proceeds minus cost basis (after adjusting for selling costs). Realized gains are reported to the IRS and taxed as short‑term or long‑term depending on holding period.
Weighted average cost (example and formula)
Weighted average cost is a common way to compute a single per‑share cost basis when you have purchased the same security at multiple prices.
Formula:
Weighted average cost per share = (Total dollars spent on purchases, including purchase commissions) ÷ (Total shares owned)
Example (paraphrasing and expanding the Investopedia example)
– Purchase 1: 100 shares at $40 = $4,000
– Purchase 2: 100 shares at $60 = $6,000
– Purchase 3: 100 shares at $80 = $8,000
Total dollars spent = $18,000 for 300 shares
Weighted average cost per share = $18,000 ÷ 300 = $60.00
If you paid purchase commissions that total $600 across the three purchases, include them:
Adjusted total = $18,000 + $600 = $18,600
Adjusted average cost per share = $18,600 ÷ 300 = $62.00
If you then sell 100 shares at $80, and you use the weighted average cost ($62) as your cost basis:
Realized gain per share = $80 − $62 = $18
Total realized gain = $18 × 100 = $1,800
Holding-period tax treatment (short vs. long term)
– Short‑term: held one year or less — taxed at ordinary income tax rates.
– Long‑term: held more than one year — taxed at preferential capital gains rates.
In the example above, if the shares were held more than one year, the $1,800 is a long‑term capital gain.
Important tax and method considerations
– Which basis method you can use depends on the security and sometimes on the account type: for mutual funds (and some dividend reinvestment plans) brokers commonly use average cost; for individual stocks, brokers typically apply FIFO unless you request a different method (e.g., specific share identification). Always confirm allowed methods with your broker.
– Brokers must report cost basis to the IRS on Form 1099‑B for covered securities. The 1099‑B will show the basis reported to the IRS and the method used. You must reconcile your records with the 1099‑B when filing.
– Selling commissions: selling commissions reduce your net sale proceeds for gain/loss calculation (or equivalently, add to the basis if you prefer to net them on the sale side).
– Corporate actions (splits, mergers, spin‑offs), reinvested dividends, return of capital, and wash‑sale adjustments affect basis and must be tracked and reflected in cost basis.
– Wash sale rule: if you sell at a loss and buy “substantially identical” stock within 30 days before or after the sale, the loss may be disallowed and added to the basis of the replacement shares. Keep records to apply this properly.
Step‑by‑step practical process for investors
1. Gather your records
• Broker trade confirmations, monthly/annual statements, Form 1099‑B, and any documentation of reinvested dividends, splits, mergers, or corporate actions.
2. Determine the purchase price(s)
• For each lot, record: purchase date, shares purchased, price per share, and purchase commissions/fees. Add commissions to that lot’s dollar total.
3. Choose and document your accounting method
• Confirm what method your broker uses by default (FIFO, average cost, specific ID). If you want specific identification, tell your broker at the time of sale which shares (purchase dates/prices) you are selling. Document the selection in writing if possible.
4. Calculate cost basis
• If you’re using weighted average: sum dollars spent on all lots (including purchase commissions) and divide by total shares.
• If using FIFO: assign basis from the earliest shares purchased.
• If using specific identification: use the exact lot basis you chosen to sell.
5. Calculate sale proceeds and realized gain/loss
• Sale proceeds = sale price × shares sold − sale commissions/fees.
• Realized gain = sale proceeds − cost basis for shares sold. (Short vs. long term depends on holding period.)
6. Check Form 1099‑B and reconcile
• Compare your calculations with Form 1099‑B from your broker. If there are discrepancies, contact the broker and gather supporting docs.
7. Report on your tax return
• Report each sale on Form 8949 when required, then summarize on Schedule D of Form 1040. Long‑term and short‑term sales are reported separately.
8. Maintain records
• Keep records for at least three years after filing (but preferably longer — generally 3–7 years or longer if adjustments are likely) so you can substantiate basis calculations if the IRS asks.
Examples of different accounting outcomes (brief)
– FIFO example: Buy 100 shares at $20, then 100 at $50. Sell 100 shares. Under FIFO you assign the $20 lot as the basis for the shares sold.
– Average cost (mutual funds): The broker may give one average cost per share for all lots; selling 100 shares uses that average as basis.
– Specific identification: You instruct the broker you are selling the 100 shares bought at $50, so your realized gain/loss is computed from that lot.
Common pitfalls and tips
– Don’t ignore commissions and fees — they adjust basis or proceeds.
– If you intend to use specific identification, make the election at the time of sale with clear instructions; retroactive elections are often not permitted.
– Reinvested dividends increase your basis — track them.
– Keep separate records for taxable accounts vs. tax‑deferred accounts (IRAs, 401(k)s behave differently).
– Use brokerage tools: many brokers provide online cost‑basis calculators and lot selection options at sale time.
– If you get a 1099‑B that shows basis “not reported to IRS,” don’t assume it’s your final tax number — reconcile and report your actual basis on Form 8949 as required.
Where to read more (sources)
– Investopedia — Purchase Price:
– IRS — Topic No. 409 Capital Gains and Losses:
– IRS — Instructions for Schedule D (Form 1040) and Form 8949 (sales and other dispositions of capital assets): and
Editor’s note: The following topics are reserved for upcoming updates and will be expanded with detailed examples and datasets.