At-the-Market (ATM) Offerings: How Companies Sell Shares a Little at a Time

The short version

An at-the-market offering, or ATM, is a standing arrangement that lets a company sell newly issued shares into the ordinary trading market whenever it chooses, at whatever the market price is at the time. A broker acts as the company's sales agent, feeding shares into the order book in small amounts over days, weeks or months.

There is no single offering day, no fixed price and usually no press release for each sale. That makes the ATM the quietest way for a public company to raise money, and one of the most common for small caps. The trade-off for shareholders is visibility: the program is announced when it is set up, but the actual selling is typically disclosed only after the fact.

The three documents behind an ATM

An ATM sits on top of a shelf registration, almost always on Form S-3. Three pieces have to exist:

1. An effective shelf. The S-3 registers securities the company may sell later.
2. A sales agreement. Often titled an Equity Distribution Agreement, At Market Issuance Sales Agreement or ATM Sales Agreement, it appoints the sales agent, sets the commission and explains how the company instructs the agent to sell. It is usually filed as an exhibit to an 8-K or to the prospectus.
3. A prospectus supplement. Filed under Rule 424(b)(5), the 424B5 states the maximum dollar amount of shares that can be sold under the program and describes the plan of distribution.

The supplement is the document most people read first, because its cover page gives the size, the agent, the exchange and the commission in a few paragraphs.

A real example from a 424B5

Planet Green Holdings Corp. filed a 424B5 on October 2, 2026 for an ATM program of "up to $22,539,922" of common stock under an ATM Sales Agreement with Craft Capital Management LLC as sales agent. The cover page described how the program works in standard language: the company "may, but are not obligated to, offer and sell new shares of our common stock," and the agent and any executing broker would be "entitled to aggregate compensation at a commission rate equal to 4.0% of the gross sales price per share sold."

Two details in that filing are typical. First, "may, but are not obligated to" means the program size is a maximum, not a commitment to sell anything. Second, the size was set by the baby shelf cap: the same document showed the company's public float calculation and a one-third limit of exactly $22,539,922.

How an ATM actually sells

Day to day, the company sends the agent a placement notice: sell up to a certain number of shares, not below a certain price, over a certain period. The agent works the order through the exchange, usually limiting itself to a fraction of daily trading volume so the selling does not dominate the tape. The company can pause or stop at any time.

That volume constraint is what sets the real pace of an ATM, more than the headline size.

A worked example: how long a $20 million ATM takes

Take a hypothetical Company X with 40,000,000 shares outstanding trading at $1.00, so a $40 million market capitalisation. It sets up a $20,000,000 ATM. Its stock trades an average of 2,000,000 shares a day, and its agent targets about 10% of daily volume.

All figures are hypothetical and assume a constant price.

Fully used at $1.00, the ATM would add 20,000,000 shares, a 50% increase in the share count. In reality the price moves. If the average sale price were $0.80 instead, raising the same $20 million would take 25,000,000 shares. If volume spiked on news, say to five times its normal level (a relative volume of 5), the agent could sell far more in a single day. ATMs tend to be used most heavily when volume is high, because that is when shares can be sold with the least price impact.

Where ATM sales show up

Because individual sales are not announced, you usually learn about ATM usage later:

• The 10-Q or 10-K. The liquidity section and the equity footnote of a 10-Q typically state how many shares were sold under the ATM during the period, the gross and net proceeds, and the remaining capacity. The cover page share count also captures it.
• Subsequent events. The notes often disclose ATM sales made after the quarter ended but before the filing date.
• 8-Ks. Some companies file an 8-K when they finish or terminate a program, or when they enter a new sales agreement.
• New supplements. When a company increases the program size or its baby shelf capacity grows, it files a new or amended 424B5.

What to look at when an ATM is filed

• Size relative to market capitalisation. A $10 million ATM is minor for a $1 billion company and very large for a $15 million one.
• The cap that applies. For a company under the baby shelf threshold, the program cannot exceed its one-third limit, whatever the shelf says.
• The commission rate. Typical rates run from about 1% to 4% of gross sales.
• Prior ATMs. A new agreement often replaces one that was exhausted. The earlier program's history shows how actively the company used it.
• Cash position. A company with a short cash runway has more reason to draw on the program.

How to check a company on Signal8

• The live SEC filings feed shows 424B5 supplements as they are filed.
• Each company's Dilution tab, for example AAPL's Dilution tab, is where Signal8 organises the ATM programs and shelf registrations it has extracted. Coverage focuses on small-cap issuers.
• The dilution screener lets you compare companies on dilution-related data.

FAQ

Does a company have to announce each ATM sale?

Generally no. The program itself is disclosed when the sales agreement and prospectus supplement are filed, but individual sales are usually reported in aggregate later, in the next 10-Q or 10-K. Some companies also file an 8-K when a program is completed or terminated. Between those filings, the pace of selling is not publicly known in real time.

Who buys shares in an ATM?

Whoever is buying in the market at that moment. The sales agent sells into the exchange like any other seller, so the buyers are ordinary market participants who usually do not know whether a particular share came from the company. That is different from a registered direct offering, where shares go to specific investors at a fixed price.

Can a company sell more than the ATM size?

Not under that prospectus supplement. To sell more, the company has to file a new or amended supplement, and it needs remaining capacity on its shelf and, if it is a baby shelf issuer, room under its one-third of public float limit. It may also raise money by other routes, such as a private placement.

Why are ATMs common among small companies?

They are cheap and flexible. Commissions are usually lower than the fees on a marketed offering, there is no fixed discount to the market price, and the company can sell only when it wants. The drawback for shareholders is that dilution arrives gradually and is reported after the fact.