VC deal flow, September 21–27: $726M across cybersecurity, back-office software, and AI biotech
Confirmed checks from a16z, Sequoia Capital, and Y Combinator reached $726 million across six rounds, led by Island's $400 million Series F and four rounds with Y Combinator in the participant list.
Six rounds announced between September 21 and September 27, 2026, carry a confirmed investment from Andreessen Horowitz, Sequoia Capital or Y Combinator, and $726 million was disclosed across them. The largest is a cybersecurity financing, and the pattern underneath the total is four rounds whose participant lists include Y Combinator. Founders Fund did not appear in any financing announced this week.
Island's $400 million Series F is 55% of the total on its own. Y Combinator appears in four of the six rounds, and three of those four sell automation for back-office work: tax filing, consumer-goods finance and recruitment operations. The remaining round is a16z's follow-on in a clinical-stage AI drug-discovery company.
A separate item: a16z incubated a school in San Francisco that raised $42 million, and it is treated outside the confirmed total.
Confirmed top-four deals
| Sector | Company | Round and terms | Tracked-firm role | What the company does |
|---|---|---|---|---|
| Cybersecurity | Island | $400M Series F, announced September 24; $6.4B valuation | Sequoia Capital: returning investor; Evolution Equity Partners led | Sells an enterprise browser and an agentic control plane that govern what employees and AI agents can reach across company systems. 1 |
| Tax compliance software | Numeral | $100M Series C, announced September 23; valuation undisclosed | Y Combinator: participating investor; Insight Partners led | Automates sales tax, VAT and GST registration, calculation and filing for companies selling across jurisdictions. 2 |
| AI drug discovery | BigHat Biosciences | $75M Series C, announced September 24; valuation undisclosed | Andreessen Horowitz: returning investor; DFJ Growth and Premji Invest co-led | Uses an autonomous lab and frontier models to design protein therapeutics, and has one program in a Phase 1 trial. 3 |
| AI data infrastructure | Firecrawl | $75M Series B, announced September 22; valuation undisclosed | Y Combinator: participating investor; Smash Capital led | Gives AI agents one interface for crawling, searching and pulling data from the live web and licensed sources. 4 |
| Consumer-goods software | Confido | $55M Series B, announced September 22; valuation undisclosed | Y Combinator: returning investor; Insight Partners led | Runs cash application, deductions, trade spend and demand planning on one data layer for consumer packaged-goods brands. 5 |
| Recruitment software | Spott | $21M Series A, announced September 22; valuation undisclosed | Y Combinator: participating investor; Balderton Capital led | Replaces separate applicant-tracking and CRM tools for recruitment agencies with one AI-native system. 67 |
Cybersecurity
Island: $400 million at a $6.4 billion valuation
Island announced a $400 million Series F on September 24, led by Evolution Equity Partners, at a $6.4 billion valuation. That is more than double the $3 billion the company carried after a $175 million round in 2024 and up from $4.8 billion after a $250 million round in March 2025. Sequoia Capital, Prysm Capital, Coatue Management, Cyberstarts, Insight Partners, J.P. Morgan Growth Equity Partners, Alta Park Capital, Georgian, G Squared and Squarepoint all returned as investors, and Dmitri Alperovitch, the former CrowdStrike chief technology officer, put in more personal money. 8
The company started with an enterprise browser that put security and IT controls inside the browser employees already used, and it is now selling a wider layer it calls an agentic control plane: one policy engine and one audit trail covering endpoints, networks, data, identity and observability. Island's co-founder and chief technology officer, Dan Amiga, put the case for the widening scope in one line to CTech: "Agents do not operate in a single layer of the technology stack, so they cannot be governed from one." 8
By September 2026 Island had reached roughly $200 million in revenue growing about 100% a year, and it counts eight of the ten largest banks as browser customers, alongside Pfizer, Chipotle and American Airlines. Headcount stands at 1,000, and chief executive Mike Fey told CNBC the company plans to reach 1,500 by the middle of next year while opening Europe, Asia and the Middle East. 18
Back-office and compliance software
Numeral: $100 million for tax filing
Numeral raised a $100 million Series C led by Insight Partners, with Salesforce Ventures, Geodesic, Benchmark, Mayfield, FCVC, Y Combinator and Uncork participating. The round brings total funding to $157 million, a year after a $35 million Series B. 2
The product handles the parts of indirect tax that companies outsource last: watching where a business crosses a registration threshold, filing returns, remitting what is owed and keeping exemption certificates current. Numeral supports VAT and GST in more than 90 countries and connects to more than 40 billing, finance and ERP systems, and it says total transaction volume rose 327% year over year. 2
Confido: $55 million for the consumer-goods back office
Confido raised a $55 million Series B led by Insight Partners, with Footwork, Trenches Capital, Watchfire, Barrel Ventures and Y Combinator returning. Total funding is now $77 million. 5
Confido's argument is about handoffs. Deduction platforms, forecasting tools and trade-promotion systems each work on their own, and the reconciliation between them is the work that breaks. Confido puts cash application, deductions, disputes, trade promotion, sales forecasting and supply planning on one set of customer, product, promotion, contract and shipment records, so a change in the forecast moves the supply plan without a second entry. More than 250 brands run on it, including divisions of Unilever, Mars and Nestlé, and the company says $30 billion of retail sales are planned on the platform. 5
Spott: $21 million for recruitment operations
Spott raised a $21 million Series A led by Balderton Capital, with Base10 Partners, Y Combinator and Fortino participating, following a $3.2 million seed round in March 2025. 6
Recruitment agencies run on an applicant-tracking system plus a CRM plus whatever lives in recruiters' inboxes. Spott collapses those into one platform and makes the existing emails, résumés and candidate databases searchable, which is where the company says the time saving comes from: it estimates human judgement accounts for about 20% of a recruiter's work, with sourcing and administration taking the rest. Spott reports revenue up more than tenfold since the start of 2026, about 20% of it in Asia-Pacific and 15% in the United States, and it plans offices in Sydney and New York. 6
AI data infrastructure
Firecrawl: $75 million to pay for the data agents read
Firecrawl raised a $75 million Series B led by Smash Capital, with Altos Ventures, Nexus Venture Partners, Y Combinator, Freestyle and Offline Ventures participating. Total funding now stands at $89.5 million. 9
Firecrawl started as a way to get clean text out of a web page for a language model, and it now has 1.5 million users. The Series B funds a product called Alexandria, which brings licensed data providers, custom connectors and Firecrawl's own indexes together behind the API its users already call, so an agent can find a source, see what it holds and pull from it without a separate integration per provider. Firecrawl pays providers such as Wikimedia Enterprise for direct access, and the new money is meant to extend that payment model to individual experts and organisations that hold data worth licensing. 4
AI drug discovery
BigHat Biosciences: $75 million for AI-designed proteins
BigHat Biosciences closed a $75 million Series C co-led by DFJ Growth and Premji Invest, with Catalio Capital Management, LG Technology Ventures and Sigmas Group joining as new investors and 8VC, Alexandria Venture Investments, Amgen Ventures, Andreessen Horowitz, Discovery Ventures, GRIDS Capital, Intermountain Ventures, Eli Lilly, Merck Global Health Innovation Fund, Quadrille Capital and Section 32 returning. Total funding is $223 million. 3
The company runs an automated lab that generates its own protein data, then uses that data to train models that propose better antibody designs. That loop has now produced a clinical program: BHB810, an antibody-drug conjugate for gastric and other gastrointestinal tumours, is in a Phase 1 trial after the first patient was dosed on September 1, and a second candidate, BHB299, is due to enter human trials in 2027. BigHat also earns from partnerships with Amgen, Merck, Johnson & Johnson, AbbVie and Lilly, which gives the round a revenue story alongside the pipeline. 3
Education
Horowitz Andreessen Academy: $42 million, and a different kind of bet
a16z announced on September 22 that it had incubated the Horowitz Andreessen Academy, a full-time school in San Francisco for people leaving high school, and that the school had raised $42 million from the firm and a group of individual investors including Adam D'Angelo, Tobi Lütke, Tony Xu, Fidji Simo, Garry Tan, Joe Liemandt and Shyam Sankar. The Academy is a for-profit company, separate from a16z, and Marc Andreessen and a16z general partner Erik Torenberg sit on its board. 1011
Gagan Biyani, who co-founded Udemy and then Maven, leads it. The first cohort, about 50 students, runs for a year from September 2027 and is tuition-free; a two-year version is planned for 2028, subject to regulatory approval, and would charge tuition in line with elite private universities. Founding partners are Anduril, Anthropic, Coinbase, Google, Meta, NVIDIA, OpenAI, Palantir, Replit and Stripe, each offering access to software, hardware, compute or hiring. Every student gets more than $50,000 in compute credits and a $5,000 travel budget. 11
The Academy sits outside a16z's venture portfolio: the $42 million goes into an institution, and the school is a separate company from the firm. Ben Horowitz framed the bet as pioneering how to train a person for the AI era, since the training built for the Industrial Revolution fits it poorly. 11
Exit watch
Venn buys Zuma for $50 million
Venn, a New York company selling AI software to real-estate operators, agreed to acquire Zuma for $50 million, the two announced on September 22. Zuma was founded in 2021 and sells agents that handle leasing enquiries, tours, renewals, rent collection and resident questions for apartment operators, and it had raised from Andreessen Horowitz, Y Combinator and King River Capital. 12
The two companies sell into the same customers from different angles. Venn builds each operator a private data layer it calls a Company Brain and runs agents on top of it, and has raised more than $140 million, including a $52 million Series B co-led by NOA and Group 11. It serves about 270 owners and operators and expects to pass a million units under management by the end of 2026. Zuma's two co-founders join Venn as general manager of leasing and chief partnerships officer, and Zuma's engineers move to Venn's core engineering team. 12
Labeled non-top-tier context
| Sector | Company | Disclosed transaction | Lead or key investors | Why it is here |
|---|---|---|---|---|
| Cybersecurity | Cyera | $400M Series G extension | Evolution Equity Partners and Goldman Sachs Growth Equity led | The week's other $400 million security round, from a company that governs data access for people and AI agents. Its participant list names none of the four tracked firms. 13 |
| AI training data | Snorkel AI | $350M Series E at a $3.2B valuation | Insight Partners and S32 led | The largest round in the AI data layer this week, in the same corner of the market Firecrawl sells into, with no tracked firm named. 13 |
| AI drug discovery | Enveda | $311M Series E at roughly a $2B valuation | Catalio Capital Management led | Doubles the valuation of a company that owns its drug candidates rather than selling discovery software, the model BigHat is also building. 13 |
| Neurotechnology | Precision Neuroscience | $250M Series D | Pershing Square and the Ackman Oxman Institute led | The week's largest medical-device financing, a brain-computer interface company with no tracked-firm investor named. 13 |
| Satellite connectivity | Hubble Network | $200M Series C at a $1.6B valuation | Smith Point Capital led | Satellite links for ordinary Bluetooth devices, one of the week's biggest space-adjacent rounds and outside the tracked firms' books. 13 |
| Pharmacy benefits | Rightway | $155M Series E | Francisco Partners led | A second healthcare-cost platform this month, after Thatch and Angle Health in the prior issue, with no tracked-firm participation disclosed. 13 |
Digest notes
- One round is more than half the week. Island's $400 million is 55% of the $726 million confirmed total. The other five rounds average $65 million.
- Three of the six rounds sell the same kind of work. Numeral files indirect taxes, Confido reconciles the consumer-goods back office and Spott runs recruitment operations. All three are replacing a stack of point tools with one system of record, and all three raised from Y Combinator in this round.
- Y Combinator's week is four positions in companies it already backed. Y Combinator appears in the participant lists for Numeral, Confido, Spott and Firecrawl. Confido's own release calls it a returning investor, Numeral's release lists it among existing shareholders, and in all four rounds another firm led.
- Cybersecurity set the price of the week. Island and Cyera each raised $400 million, and both rounds were led by Evolution Equity Partners, which puts the two largest American rounds of the week in the same sector and under the same lead.
- a16z's two appearances are a follow-on and an institution. The firm returned to BigHat's cap table and funded a school it incubated. It led no venture round this week.
- Founders Fund was absent. No financing announced between September 21 and 27 named the firm as an investor. Its most recent named round remains EnduroSat's $205 million financing on September 17. 14
Coverage note
This issue covers financing announcements and corporate developments dated September 21–27, 2026. The confirmed total counts rounds announced inside that window whose participant lists name Andreessen Horowitz, Sequoia Capital or Y Combinator: $726 million across six rounds. Founders Fund is named in no round inside the window.
Three kinds of item are kept out of that total and labeled where they appear: the Horowitz Andreessen Academy's $42 million, because it is an incubated institution outside the venture portfolio; the Zuma acquisition, because it is an exit rather than a financing; and the rounds in the context table, because their participant lists name none of the four tracked firms. Reported or unconfirmed financings are excluded entirely.
Sources for the context table come from a weekly roundup whose own reporting period is September 19–25; every item in it was checked against a second dated announcement or outlet report and falls inside this issue's window.
References
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- 2Numeral Announces $100 Million Series C Funding Round
cpapracticeadvisor.com
- 3
- 4Introducing Alexandria and our $75M Series B
firecrawl.dev
- 5
- 6
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- 8
- 9The Weekly Notable Startup Funding Report: 9/28/26
alleywatch.com
- 10
- 11
- 12Venn acquires a16z-backed Zuma for $50 million as its platform closes in on one million homes
markets.businessinsider.com
- 13
- 14Founders Fund: funding rounds led and joined in 2026
afterraise.com
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