Free course · Lesson 1 · 10 min

What a stock actually is, and how you make money from one

Own a slice of a coffee shop, see the two ways it pays you, watch time do the heavy lifting, then dodge the three classic beginner mistakes.

Written by the StockEducation Editorial Team · Reviewed by Associate Professor Charles Lo, CPA, PhD · Updated 2 Oct 2026 · How we check lessons

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Idea 1 of 4

A stock is a slice of a business

Picture a small coffee company called Common Ground. It is worth $10,000, cut into 1,000 equal slices called shares, so each share is worth $10.

Your $100 buys 10 shares, so you own 1% of the company. That is 1% of the coffee machines, the brand, the profits and the problems. Not a coupon, not a loan, not a bet on a number.1

The share price is simply what the last buyer and seller agreed on. It moves when people change their minds about the company’s future.

Try the ownership example

Your $100 in Common Ground

Fictional company
  1. Business worth$10,000
  2. Split into 1,000 shares, so one share is worth$10
  3. Your 10 shares are worth$100

Each square is 10 shares. The lit squares are yours.

Five years on, the business is worth…

The rule

A ticker is a label. A share is ownership. Think like a part owner, not a gambler.

Apply this idea in real life

In real lifeA coffee chain on the stock market works the same way, just with far more shares. One share is a real, if tiny, piece of every store.

Try this todayPick a company you use every day. Divide your budget by its share price: that is how many slices you could own.

Is a $5 stock cheaper than a $500 stock?

No. One share’s price tells you nothing on its own. What matters is what the whole business is worth, and that depends on how many shares there are.

The “cheap” $5 share belongs to the company worth ten times more.

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Idea 2 of 4

Two ways you make money. Two ways you lose it.

The price goes up. If someone will now pay $12 for your $10 share, you have gained $2 a share. That is a capital gain. You only lock it in when you sell, but a price fall is a real loss of value either way.

The company pays you cash. Some companies share part of their profit with shareholders, and many US companies pay every three months. That is a dividend. Not every company pays one, and any company can cut it.

One $10 share over a year, before fees and taxes. Either engine can run in reverse, which is how you lose: prices fall and dividends get cut.
Try the gains and dividends example

Your $100, one year later

Drag the sliders
$0You paid $10$20
None$2
Price change+$20
Cash paid to you+$5
Total return+25%

The formula

Total return = price change + dividends, before fees and taxes.

Apply this idea in real life

In real lifeYour broker app shows both engines: the price line is engine one, the small cash deposits every few months are engine two. Most beginners only watch the first.

Try this todayOpen any stock page and find its dividend yield. Zero means it only pays you through the price.

Marks Idea 2 done

Idea 3 of 4

Time beats timing

Say your money grows 7% in a year. $1,000 becomes $1,070. Next year’s 7% is earned on $1,070, not $1,000, so you reach $1,145. That is compounding: growth on growth. Small at first, then not small at all.

Your $1,000Earlier growthGrowth that decade
$1,000 left alone at 7% a year. Each decade’s growth is bigger than the last, because it grows on everything before it.

Two things drive it: how long you stay invested and how regularly you add. Neither needs a prediction.

Real market example: a loss and a recovery in 2008 and 2009

The S&P 500’s total return, including dividends, was −36.55% in calendar 2008 and +25.94% in calendar 2009 in NYU Stern’s historical dataset. Apply those reported returns to an illustrative fixed $1,000 balance at the start of 2008:

  1. After 2008: $1,000 × (1 − 0.3655) = $634.50.
  2. After 2009: $634.50 × (1 + 0.2594) = $799.09, rounded to cents.
  3. Across both years: ($799.09 ÷ $1,000 − 1) × 100 ≈ −20.09%. A positive second year did not erase the first year’s loss.
The same $1,000 through two calendar years
DateYear’s returnBalance
Start of 2008Starting amount$1,000.00
End of 2008−36.55%$634.50
End of 2009+25.94%$799.09

Source: NYU Stern, Aswath Damodaran: Historical Returns on Stocks, Bonds and Bills, 2008 and 2009 rows, retrieved October 9, 2026. The returns are historical; the $1,000 balance is a teaching calculation, not an actual investor account. It assumes reinvested dividends, no additions or withdrawals, and excludes fund fees and personal taxes. An index cannot be bought directly. Past performance does not predict future returns. The amount picker controls the interactive models, not this fixed historical example.

$100 now + $100 a month

A model, not a forecast

$100 a month until 65: start at 25 or at 35?

Money put inGrowth on top
Same 7% a year for both. Ten extra years of $100 a month, $12,000 in all, ends up worth about $130,000 more. A model, not a forecast.
The rule

Start early, add regularly, leave it alone. Nobody reliably picks the perfect moment.

Apply this idea in real life

In real lifeAn automatic monthly transfer into an index fund is how most people actually do this. Nobody watches the market; the calendar does the work.

Try this todayPick a monthly amount you could set and forget. Slide it into the model above and read the 30 year number out loud.

Marks Idea 3 done

Idea 4 of 4

Three mistakes to dodge

Ideas 1 to 3 grow money. These three habits lose it. Each has a simple fix.

1Everything in one company

Even great companies stumble. If one company halves and it is all you own, you lose half.

FixSpread across many companies. One fund can do it for you, and the course shows you how.5
2Money you need soon

Since 1980 the S&P 500 has dropped about 14% inside an average year, then finished higher in 35 of 46 years.2 A bill that forces you to sell at the low turns a dip into a real loss.

FixInvest only money you can leave alone for five years or more.
3Believing “guaranteed”

US stocks have averaged roughly 10% a year over the long run, with big losing years on the way.3 A promise of more, with no risk, is a classic red flag.7

FixGuaranteed, high and urgent together means walk away, then check the seller through official sources like Investor.gov.
Check your readiness before investing real money

Before your first real dollar

Tick what is true for you today. Your ticks stay on this device.

Marks Idea 4 done

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You finished Lesson 1.

You know what a share represents and why both gains and losses are possible. Keep learning in the next lesson.

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Lesson 1 complete

Now learn the rest in the right order

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  1. Step 1 · DoneLesson 1: what a stock is
    See the lesson on one card
    1. A stock is a slice of a business. 10 of 1,000 shares is 1%. The price is what the last buyer and seller agreed.
    2. You earn two ways. The price rises (capital gain) or the company pays cash (dividend). Total return is both.
    3. Time beats timing. Returns earn returns. Start early, add monthly, leave it alone.
    4. Dodge three mistakes. All in one company, money you need soon, anything “guaranteed”.
    5. Before your first dollar: emergency cash, no high interest debt, five years or more.
  2. 2
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Want the full sequence? See the course outline →

Need a definition? Glossary Sheet (reference) →

Sources and assumptions
  1. SEC Investor.gov: Stocks
  2. J.P. Morgan Asset Management, Guide to the Markets: S&P 500 intra year declines vs. calendar year returns, 1980 to 2025 (average drop 14.2%, positive in 35 of 46 years), as of 30 March 2026
  3. NYU Stern, Aswath Damodaran: Historical returns on stocks, bonds and bills, 1928 to 2025, updated 5 January 2026. S&P 500 with dividends: $100 at the start of 1928 grew to about $1.16 million by the end of 2025, about 10% a year; in 2008 it fell 36.55%.
  4. Federal Reserve G.19 Consumer Credit, 8 September 2026: interest rate on credit card accounts assessed interest, 22.15%, second quarter 2026
  5. Investor.gov: Diversification
  6. Investor.gov: Compound interest calculator
  7. Investor.gov: Red flags of investment fraud checklist

Common Ground and all its prices are fictional, in US dollars. Calculators use one steady yearly return, deposits at the end of each month, and no fees, taxes or inflation; check any figure with the Investor.gov calculator.6 Past returns never guarantee future results. Figures checked 24 September 2026.

StockEducation provides general education, not personal financial, tax or legal advice. Nothing here recommends a specific security or allocation. Investing involves risk, including the loss of money you invest.

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