A capital gain is realized when an investor sells a security for more than its original cost. When you hear “buy low, sell high,” that’s the idea. If the investor sells for less than the original cost, it’s a capital loss.
A gain or loss is realized when the position is closed:
A long position is closed when the security is sold. A short position is closed when the security is bought back.
To determine the gain or loss, investors compare cost basis to sales proceeds.
Cost basis is the total amount paid to buy the security, including any commission. Sales proceeds is the total amount received from selling the security, minus any commission.
In other words, cost basis is what you paid in, and sales proceeds is what you got out. Let’s apply that in an example.
An investor purchases shares of ABC stock at $50 while paying a $2 per share commission. Several months later, the stock is sold for $70 while paying another $2 per share commission. What is the cost basis, sales proceeds, and capital gain or loss?
Can you figure it out?
(spoiler)
Cost basis = $52 The cost basis equals the purchase price ($50) plus the commission ($2). This is the total amount paid to buy the shares.
Sales proceeds = $68 Sales proceeds equal the sale price ($70) minus the commission ($2). This is the total amount received from selling the shares.
The capital gain or loss = $16 capital gain The gain or loss is sales proceeds minus cost basis: $68 - $52 = $16. A positive number is a capital gain; a negative number would be a capital loss.
Capital gains can be long-term or short-term. Long-term capital gains apply to securities held for longer than one year. In practice, the holding period must be one year and one day to be long-term. Long-term capital gains are taxed the same way as qualified dividends: 0%, 15%, or 20%, depending on the investor’s annual income level.
Sidenote
Vague test questions You may see a test question about long-term capital gain tax rates that doesn’t specify the investor’s income level or the exact rate. In that case, assume a 15% rate for long-term capital gains. Bottom line: assume a 15% tax rate on qualified dividends or long-term capital gains unless the question indicates otherwise.
Short-term capital gains apply to securities held for one year or less. Short-term capital gains are taxed at the investor’s ordinary income tax rate (the investor’s marginal tax bracket), which can be as high as 37% (similar to non-qualified dividends). Because the tax rate is often lower, investors generally prefer long-term capital gains. As a reminder, these are the income tax brackets for individuals and those filing jointly in 2025:
Rate
Individuals
Married filing jointly
10% $0 $0
12% $11,926 $23,851
22% $48,476 $96,951
24% $103,351 $206,701
32% $197,301 $394,601
35% $250,526 $501,051
37% $626,351 $751,601
Do not memorize these tax brackets; this chart is only for context.
Marginal tax bracket
The tax bracket applied to the last dollar earned
Capital gains are reported on Form 1099-B (B stands for brokerage proceeds). Each year, brokerage firms report customers’ capital gains and losses to the IRS. If the investor has more gains than losses (a net capital gain), they owe taxes. If the investor has more losses than gains (a net capital loss), the loss can be used as a deduction.
Sidenote
Inherited securities Death is an unfortunate aspect of life, but the IRS reduces tax burdens on inherited securities in two important ways:
Cost basis is “stepped up”
The holding period is automatically long-term
When an investor dies, their assets pass to beneficiaries. The beneficiary’s new cost basis is the security’s value on the date of the original owner’s death. The beneficiary’s holding period is treated as long-term, no matter how long the original owner held the investment.
Key points
Capital gain
Securities sold for more than the basis
Reported on tax form 1099-B
Long-term capital gain
Gain on security held more than 1 year
Tax rate: 0%, 15%, or 20%
Short-term capital gain
Gain on security held for 1 year or less
Tax rate: up to 37%
Inherited securities
Cost basis is stepped up to the value on the date of death
Holding period is always long term
A capital gain is realized when an investor sells a security for more than its original cost. When you hear “buy low, sell high,” that’s the idea.