Market cap and dilution: who pays for the new slices.

01AMC: five times the shares

In 2020 the pandemic shut AMC's movie theaters for months. With almost no tickets sold and the bills still due, AMC Entertainment did what companies short of cash do: it sold new shares. A lot of them.

In 2019 AMC had about 104 million shares on average. In 2020 it sold 91 million new shares into the stock market, raising $272.8 million. In January 2021 it sold about 187 million more, for $596.9 million, and $600 million of its bonds converted into another 44 million shares. By August 2021 it had more than 513 million shares, about five times as many as two years before.

Then the stock became a meme, rising from under $2 early in 2021 to many times that by June. AMC kept selling. On June 3 it said it had sold 11.55 million shares at an average of about $50.85, raising $587.4 million. The day before, the stock had risen 95%; that day it fell almost 40% in the morning and closed down 17.9%.

Every one of those sales made each existing share a smaller slice of AMC. Some shares were sold for about $3, to survive a crisis; some for more than $50, to buyers in a frenzy. Five times the shares sounds like a disaster for anyone who owned the stock in 2019. Whether it was comes down to one number per sale: the price.

02Market cap: the price tag on the whole company

A share is a slice of a company. Multiply the price of one slice by the number of slices and you get the market cap, the stock market's price for the whole business.

Take a pizza company with 10 million shares trading at $10. Its market cap is $100 million. It made $5 million of profit last year, so its earnings per share are $0.50. You own 100,000 shares: 1% of the company, worth $1 million.

Market cap can change for two reasons: the price moves, or the number of shares does. The share price alone tells you nothing about size. A $500 stock can belong to a smaller company than a $20 one; it may just have fewer shares.

03Dilution: more slices of the pizza

Picture the company as a pizza cut into 10 million slices, and you hold 100,000 of them. Now the company sells 2.5 million new slices. You still hold 100,000, but there are 12.5 million in all, so your share of the company falls from 1% to 0.8%. That is dilution: the same number of shares, a smaller share of the company. Your claim on its profits, its dividends and its votes shrinks with it.

But a share sale does not just cut the pizza into more slices. The buyers pay for the new slices, and that cash goes into the company. A smaller slice of a bigger pizza can be worth exactly what your old slice was. Whether it is depends on the price.

04Who pays: price against worth

Same company, worth $10 a share. Three ways it might sell 2.5 million new shares:

Sold at what they're worth, the new shares bring in exactly their value. Your slice is smaller, the pizza is bigger, and your $1 million is still $1 million. Sold at a discount, the new buyers pay $8 for shares that end up worth $9.60. Their $1.60 gain on each new share, $4 million in all, comes out of the existing owners' pockets: 40 cents on each of their 10 million shares. Sold at a premium, it runs the other way: the newcomers pay $12.50 for shares worth $10.50, and their $5 million of overpayment lands in the existing owners' slices, 50 cents a share.

The table uses $10 as both the market price and what the company is really worth, because in the example they're the same. In real life they aren't. The price is a quote; the worth is an estimate. The test is the worth: sell shares for more than the business is worth per share and the buyers have paid for part of your pizza; sell for less and you've paid for part of theirs. A sale below the market price is the everyday case of selling for less. Outside the US, companies often offer discounted shares through a rights issue: existing owners get first claim on the new shares, in proportion to what they already hold, and where the right can be traded they can sell it instead. The discount then costs you only if you neither take up nor sell your right.

Two more ways shares get created. A company can pay for another company in its own shares, making the target's owners part-owners of the buyer. And convertible bonds and warrants can turn into shares later. The fully diluted share count counts all of these in advance, which is why an income statement shows two earnings-per-share figures: basic, on the shares that exist, and diluted, as if the options and convertibles that would lower it had already become shares (options counted net of the cash they would bring in).

The rule of thumb: dilution at or above what the shares are worth, for cash put to good use, costs you nothing. Dilution below it, or for cash that gets wasted, does.

Back to AMC. Its 2020 and January 2021 sales raised about $870 million for 278 million new shares, around $3 each, to get through a crisis. Its June 3, 2021 sale raised $587 million, two-thirds as much, for 11.55 million shares, about a twenty-fourth as many. For anyone who already owned the stock, whether each sale cost them depends on the question this section asks: was the price above or below what a slice of AMC was worth at the time?

05Why the price often drops on the news

Announce a share sale and the stock often falls the same day. Four reasons, usually together:

• The discount. Selling millions of shares at once takes a price below the market, and the new, lower price pulls the old one down.
• The signal. Management knows the business best. If they're selling shares, investors ask whether they think the price is high, or whether the company needs money more than it said.
• The math. Earnings per share drop at once; the profit from the new cash comes later, if at all.
• The supply. More shares are looking for buyers on the same day.

It isn't always bad news. A raise that pays for a clearly profitable project, or ends the fear that the company might run out of cash, can lift the price.

06Buybacks: the same trade in reverse

A buyback is the company using its cash to buy its own shares and retire them. Fewer slices, and a pizza that's smaller by the cash spent. Say the company spends $25 million:

At a fair price a buyback creates nothing by itself: it hands cash to the shareholders who sell, and those who stay own a bigger slice of a smaller pizza. Earnings per share rise, from $0.50 to $0.67 here, because the same profit is split fewer ways (assuming the cash spent wasn't earning anything; any interest it earned is lost). The value per share only rises if the company buys below what the shares are worth, and falls if it overpays.

Companies buy back shares to return cash without promising a dividend they'd have to keep paying, to soak up the shares they issue to employees, and to signal that they think the stock is cheap. There's a tax reason too: a dividend is taxed when it's paid, while a buyback lets each owner choose when to sell, and so when to pay tax. And there's an incentive to watch: executives holding stock options, which collect no dividends, gain more from a buyback than from the same cash paid out as a dividend. The way to see what's really happening is the share count over the years, not the size of the buyback headline. A company that buys back $10 billion of stock and issues $10 billion to employees hasn't shrunk its share count at all.

Apple is the biggest example. Adjusted for its two stock splits since, it had about 26.1 billion shares in its 2013 fiscal year and about 15.0 billion in fiscal 2025: 42% fewer. Over those thirteen years it spent about $816 billion buying back its own stock, while still paying its employees partly in shares: $12.9 billion of stock-based compensation in fiscal 2025 alone. Our Apple report has the current figures.

07Splits are not dilution

In a 2-for-1 stock split, every share becomes two. Your 100,000 shares at $10 become 200,000 at $5. The pizza is the same; every slice was cut in half, yours included. You still own 1%, worth $1 million. A reverse split works the other way: 1-for-10 turns ten shares into one, usually because the price has fallen so low that the stock risks being removed from its exchange (Nasdaq and the New York Stock Exchange both require at least $1 a share).

08What it does to related securities

09Try it: issue or buy back

Set the company, then sell new shares or buy some back at any price. "Company worth" is what the business is really worth; the price is what the deal gets. The gold line shows the share price afterward for every possible price; the dashed line is the price before. Where the gold line crosses it, the deal is fair.

Four things to try. Set the price to $10, what the shares are worth, and the share price doesn't move, however many you sell. Set it to $15 and watch your stake rise: the buyers paid for part of your pizza. Set it to $0 for shares that bring in no cash at all. Then switch to a buyback at $12.50 and watch the owners who stay pay for the overpayment.

10Common misreads

• "Dilution always hurts." Not at a fair price with the cash well used. The slice shrinks; the pizza grows.
• "They sold shares at the top, so they ripped off their shareholders." The people who already held the stock weren't the ones paying the high price; the buyers were. Owners are hurt when shares sell cheap, not dear.
• "The market cap went up, so shareholders got richer." Not if it went up because new shares were sold. In the first example the market cap rose 25% and your $1 million stayed $1 million.
• "Buybacks always help." Only bought below value, and only if they shrink the share count rather than offset stock pay.
• "A split makes the stock cheaper." Each share costs less; the company costs exactly the same.
• "A $5 stock is cheaper than a $500 one." The share price alone says nothing. Compare market caps, or price to earnings.