How Startup Funding Rounds Work, From Pre-Seed to Series C
Each round sells a slice of the company to new investors at a new price. Here is what the round names mean, who writes the checks and how founders' stakes shrink along the way.
A startup funding round is a sale of new shares, or of instruments that later become shares, to outside investors at an agreed price. Companies usually move from pre-seed and seed rounds, which pay to build a product, to Series A, B and C rounds, which pay to grow it. A Form D filed with the SEC often confirms the amount.
The letters are a convention, not a legal category. A “Series A” is simply the first round of preferred stock sold at a set price, and companies name later rounds alphabetically. Some skip letters, some add extensions such as “Series A-1”, and many now raise a seed round larger than an older generation’s Series A.
What is each funding round for?
Each stage pays for a specific milestone that should make the company worth more at the next raise.
| Round | Usual purpose | Typical investors | Common instrument |
|---|---|---|---|
| Pre-seed | First product, first hires, early tests with customers | Founders, friends and family, angels, accelerators | SAFE or convertible note |
| Seed | Finding product-market fit and early revenue | Angels, seed funds, accelerators | SAFE or a priced seed round |
| Series A | Turning a working product into a repeatable business | Venture capital firms, usually one lead | Preferred stock |
| Series B | Scaling sales, hiring, new markets | Larger VC firms, sometimes the Series A lead again | Preferred stock |
| Series C and later | Expansion, acquisitions, preparing for an IPO or sale | Growth funds, crossover funds, corporate investors | Preferred stock, sometimes with structured terms |
Early rounds often use a SAFE, which delays setting a price until a later round. Our guide to what a SAFE is shows how that conversion works.
How big are typical rounds right now?
Round sizes vary widely by sector and year, so any “typical” number is a midpoint of a broad range. Carta, which runs cap table software for private companies, published medians on July 10, 2026 for software startups that raised in the previous six months, excluding bridge rounds and extensions (Carta data archive).
| Stage | Median cash raised | Median valuation |
|---|---|---|
| Seed | $4.1 million | $24.3 million |
| Series A | $14.4 million | $80 million |
| Series B | $25 million | $191 million |
| Series C | About $40 million | $391 million (post-money) |
| Series D | $63 million | $789 million |
These figures cover only companies that use Carta and only software. Biotech, hardware and consumer startups follow different patterns, and the top end of each stage is far above the median. Carta’s same release noted that a large share of the sample works on AI, which pulls valuations up.
What does “led by” mean in funding news?
The lead investor is the firm that sets the price and main terms of the round and usually writes the largest check. Other investors join on the same terms.
The lead negotiates the term sheet with the founders. It often takes a board seat, and its name signals to other investors that someone has done detailed due diligence. When a headline says “Series B led by Firm X, with participation from Y and Z,” Y and Z bought shares in the same round at the price the lead agreed.
Existing investors frequently put more money in later rounds to keep their percentage. That is called exercising pro rata rights, where the investment documents give them.
How does dilution work across rounds?
Dilution is the drop in an existing holder’s percentage when the company issues new shares. The holder keeps the same number of shares, but the total grows.
A simplified example with made-up numbers and no option pool:
- Two founders own 100% of 10 million shares.
- A seed fund invests $4 million at a $20 million post-money valuation. It buys 20% of the company, so the founders now hold 80%.
- A Series A firm invests $15 million at a $75 million post-money valuation, buying 20% of the company after the round.
- Everyone who owned shares before the Series A keeps 80% of what they had. The founders fall from 80% to 64%, and the seed fund from 20% to 16%.
In real rounds, investors usually also ask the company to create or enlarge an employee option pool before the money comes in, which dilutes existing holders a bit more. The difference between the price before and after the new money is explained in our guide to pre-money vs post-money valuation.
What do investors get besides shares?
From Series A onward, investors usually buy preferred stock, which comes with rights that common stock held by founders and employees does not have.
- Liquidation preference: in a sale, preferred holders are paid back first, often 1x their investment, before common holders get anything.
- Board seats and votes on major decisions, such as selling the company or raising more money.
- Anti-dilution protection if a later round is priced lower (a “down round”).
- Information rights to regular financial reports.
These terms matter in an exit. A company sold for less than the total invested can leave little or nothing for common stock, which is why our guide to stock options in an acquisition tells employees to look for the preference stack.
Where can you check a startup’s funding round?
Most venture rounds rely on Regulation D, and the company must file a short Form D notice with the SEC within 15 days after the first sale. It lists the amount sold and the number of investors, but not the valuation or the investors’ names. Press releases and the company’s own announcements give the lead investor and use of funds; valuations are disclosed only when the company or its investors choose to share them.
Private companies do not publish full financial statements. Numbers in funding stories that do not come from the company or a filing are usually attributed to people familiar with the deal, and they stay reports until confirmed.
Bottom line
When you read a funding headline, check three things: whether the valuation is pre-money or post-money, who led the round, and whether the round was priced or used SAFEs. If you hold equity in a startup, your option grant or stock agreement and the company’s cap table show your actual percentage; ask the company’s equity administrator how the latest round changed it.
FAQ
What comes before a seed round?
Pre-seed money usually comes from the founders, friends and family, angel investors or an accelerator. It is often raised on SAFEs and pays for a first version of the product.
How much of the company do founders sell in each round?
Carta’s July 2026 data put median dilution at about 18% for software seed and Series A rounds, and lower at later stages. Individual deals range widely around those medians.
Can a company skip Series A?
Yes. Round letters are labels the company chooses, and a business that grows on its own revenue or gets acquired early may never raise a Series A. Some companies also raise unlabeled “growth” rounds.
Is a bridge round a bad sign?
Not always. A bridge or extension adds money between lettered rounds, sometimes to reach a milestone, sometimes because a new round is hard to raise. The terms, especially the price compared with the last round, tell you more than the label.
