A Series A is the first large, priced round of venture capital a startup raises after its seed funding. Investors buy a new class of shares, normally called Series A Preferred Stock, at a price that sets a formal valuation for the company. The round exists to fund the step from an early product with some evidence of demand to a business that can be scaled, and it marks the point at which institutional venture firms typically take board seats and negotiated legal rights.

The letter is literal. Each new class of preferred stock a company issues is designated with the next letter of the alphabet, so the next priced round becomes Series B, then Series C and onwards. Anthropic, for instance, reached its sixth major institutional round, a $13 billion Series F at a $183 billion valuation, in September 2025.

How a Series A round works

The process usually starts with a term sheet, a short, mostly non-binding document from a lead investor that sets the headline price and rights. The lead normally writes the largest cheque, negotiates the terms, and takes a board seat. Other investors, including seed funds exercising their right to keep their ownership percentage, fill out the rest of the round.

The arithmetic runs through two numbers. The pre-money valuation is what the company is deemed to be worth before the new cash arrives; the post-money valuation adds the investment. A company raising $12 million on a $48 million pre-money valuation has a post-money valuation of $60 million, and the Series A investors own 20%. The price per share equals the pre-money valuation divided by the fully diluted share count, which includes options and, often, an enlarged employee option pool. When that pool is expanded inside the pre-money figure, the dilution falls on existing holders rather than on the new investors, a mechanism lawyers call the option pool shuffle.

Earlier instruments convert at this moment. Seed investors who used convertible notes or SAFEs (simple agreements for future equity) receive Series A shares, typically at a discount or at a capped valuation set when they invested.

Once terms are agreed, lawyers draft the closing documents. In the United States, the starting point is usually the model set published by the National Venture Capital Association (NVCA): an amended certificate of incorporation that creates the new share class, a stock purchase agreement, an investors' rights agreement, a voting agreement, and a right of first refusal and co-sale agreement.

The terms that come with preferred stock

Preferred stock differs from the common stock held by founders and employees in several ways:

  • Liquidation preference. On a sale or wind-down, preferred holders receive their money back before common holders receive anything. According to Cooley's Q1 2026 venture financing report, 98.2% of the 165 deals it handled carried a 1x preference and 96.4% used non-participating preferred, meaning investors take either their money back or their converted share of proceeds, not both.
  • Conversion. Preferred shares can convert into common, which investors choose when an exit is large enough that ownership beats the preference.
  • Anti-dilution protection. If a later round is priced lower, a formula adjusts the conversion price. The broad-based weighted-average version is the market norm; the harsher full-ratchet version is rare.
  • Protective provisions. Series A holders gain vetoes over actions such as selling the company, issuing senior shares or changing the charter.
  • Governance and information. Board seats, financial reporting rights and pro rata rights to invest in future rounds.

Dilution is the founder's cost. Carta put median Series A dilution at about 18% in the first quarter of 2026, down three to five percentage points over three years.

Typical sizes, timing and investors

According to Carta's State of Private Markets report for Q1 2026, US startups on its platform raised $7.0 billion across 369 Series A rounds, compared with $6.2 billion across 444 rounds a year earlier. The median Series A post-money valuation was $63 million. Medians diverge sharply by sector: $7 million raised for non-AI companies, $8.9 million for applied AI, and $40 million for companies building foundation models, whose median post-money valuation was $300 million. The typical gap between seed and Series A stood at two years.

Those medians hide a long tail. In January 2026, Crunchbase News reported that more than 40% of combined seed and Series A investment so far that year had gone to rounds of $100 million or more, including a $300 million Series A for Ricursive Intelligence at a $4 billion valuation.

Investors span venture capital firms, corporate venture arms and specialist funds, often run by former operators. Sir Martin Sorrell's S4S Ventures, for example, led Olyzon's $10 million Series A to build an agentic buying platform for connected TV.

Investors typically assess commercial traction at this stage. For software businesses, that usually means annual recurring revenue, its growth rate and retention, the metrics around which SaaS companies are valued.

Origin and evolution

Organised venture capital is usually dated to June 6, 1946, when Georges Doriot, Karl Compton and Ralph Flanders founded American Research and Development Corporation in Boston. Its 1957 investment of $70,000 for 70% of Digital Equipment Corporation became the model for staged equity financing. The NVCA followed in 1973.

Seed financing was later formalised beneath the Series A. In 2010, Fenwick & West lawyer Ted Wang published the open-source Series Seed documents with backing from Andreessen Horowitz. Y Combinator introduced the SAFE in late 2013 and replaced it in 2018 with a post-money version that fixed the SAFE holder's ownership.

Cheaper seed money produced a bottleneck. In December 2012, Fortune's Dan Primack, using CB Insights data, reported that Series A deals had fallen to 65% of the prior year's seed and angel deal count, from 91% in 2011. The episode became known as the Series A crunch.

The NVCA updated its model documents on October 2, 2025, adding provisions for milestone-based tranched financings, representations covering US outbound investment and data security rules, and language reflecting an expanded qualified small business stock tax exclusion, according to law firm Foley & Lardner.

Why it matters to the marketing community

Series A rounds finance much of the ad tech and martech supply chain before it reaches scale. PPC Land has recorded the pattern across categories: AdQuick's $6 million Series A in February 2020 for programmatic out-of-home; Didomi, whose $6 million Series A preceded a $40 million Series B for consent management in July 2021; and Seedtag, whose $5.2 million Series A in 2017 led to a $40 million Series B in 2021 and a controlling investment of more than 250 million euros from Advent International in 2022.

For media buyers, a vendor's funding stage signals runway, pricing pressure and the probability of acquisition or shutdown. A Series A company typically has around two years of cash and must show growth to raise again.

Limitations, criticisms and disputes

The label carries no fixed meaning. A $7 million round for a software tool and a $300 million round for an AI laboratory share the same name, which makes "Series A" a poor proxy for maturity.

Preferences can hollow out employee equity. In a modest sale, a 1x preference stacked across several rounds can absorb most proceeds, leaving common holders with little. Pay-to-play provisions, which penalise investors who skip later rounds, appeared in 7.3% of Cooley's Q1 2026 deals, and down rounds in 11.4%.

Data sources disagree. Carta measures companies using its software; Crunchbase and PitchBook rely on announced and filed rounds; and some companies relabel rounds as "seed extensions" to avoid a Series A at a lower valuation.

Concentration is a further dispute. According to Crunchbase, AI companies took $102 billion, or 64%, of $159 billion in global venture funding in Q3 2026. In crypto, by contrast, the median Series A round size fell by more than half during 2024, according to Outlier Ventures data cited by PPC Land.

Series A versus adjacent terms

Recent developments

Early-stage funding is rising again. Crunchbase reported on October 5, 2026 that Series A and B rounds totalled $40.6 billion globally in Q3 2026, up 25% from a year earlier, while seed funding reached $13 billion. Carta reported in July 2026 that Series A valuations hit a record in the second quarter, with the top 5% of rounds above $500 million post-money.

The money is narrowly spread across marketing technology. PPC Land reported in May 2026 that sales, marketing and CRM startups raised about $3.7 billion by early May, with a handful of large later-stage rounds accounting for much of it. Equity-free alternatives have also appeared; Google DeepMind's robotics accelerator, launched in June 2026, offers mentoring and cloud credits without taking shares. Apostra, formerly Scope3, said in September 2026 that it expects to seek more funding before mid-2027.

Timeline

  • June 6, 1946 - American Research and Development Corporation is founded in Boston.
  • 1957 - ARD invests $70,000 for 70% of Digital Equipment Corporation.
  • 1973 - The National Venture Capital Association is founded.
  • 2010 - Ted Wang publishes the open-source Series Seed documents.
  • December 5, 2012 - Fortune reports the "Series A crunch", with Series A deals at 65% of the prior year's seed count.
  • Late 2013 - Y Combinator introduces the SAFE.
  • 2017 - Seedtag closes a $5.2 million Series A.
  • Fall 2018 - Y Combinator releases the post-money SAFE.
  • February 2020 - AdQuick raises a $6 million Series A.
  • October 2, 2025 - NVCA updates its model legal documents.
  • Q1 2026 - Carta records 369 US Series A rounds worth $7.0 billion, with a $63 million median post-money valuation.
  • May 2026 - S4S Ventures leads Olyzon's $10 million Series A.
  • October 5, 2026 - Crunchbase reports $40.6 billion of Q3 2026 Series A and B funding, up 25%.

Summary

Who: Startups that have completed seed funding, lead investors such as venture capital firms and corporate venture arms, and the founders and employees whose common stock is diluted.

What: The first major priced venture round, in which investors buy Series A Preferred Stock carrying a liquidation preference, conversion rights, anti-dilution protection, vetoes and usually a board seat.

When: Typically about two years after seed, according to Carta. The model traces to ARD's founding in 1946; seed instruments arrived in 2010 and 2013, and NVCA's model documents were last broadly updated on October 2, 2025.

Where: Most heavily in the United States, using Delaware corporate law and NVCA documents, though the same structure is used across Europe and elsewhere, including by ad tech firms such as Seedtag and Didomi.

Why: It funds the move from early traction to scale, prices the company for the first time, and sets the investor rights that shape every later round and exit.