Demo Day is here (Thursday, September 10th) and we’ve taken a closer look at YC’s Summer 2026 batch: 250 companies and 508 founders.
Gravity’s dataset has ~250 companies and just over 500 founders, and the pedigree is dense: the co-founder of Hyperloop One, the founding CEO of Atomwise, the team that built Scythe Robotics, the hardware crew behind Humane’s AI Pin, a co-founder of Branch, and the founder of OwnLocal are all in this batch, alongside a wall of MIT/Stanford/Berkeley lab researchers and ex-Jane Street / Citadel / Morgan Stanley quants.
The themes: defense and drones, robots that do physical labor, “rebuild this regulated industry around a model,” and a deep bench of inference / eval / training-data infrastructure.
Below are the categories and the companies and founders worth knowing. Full dataset at the end.
1. Defense, Aerospace & Space
Ethos Space - Making silicon on the Moon to feed space-based energy demand.
Team: CTO Brogan Bambrogan co-founded Hyperloop One and Arrivo; CEO Ross Centers ran the Planetary Sunshade Foundation and founded Radiant Lunar.Hop Aero - Rockets that deliver cargo anywhere on Earth in minutes.
Team: Founders out of SpinLaunch, Masten Space Systems, Supernal, DZYNE and Destinus.Edgerun Industries - Military exoskeletons.
Team: Founder David Venegas co-founded Durin and was early engineering at Hadrian and Stoke Space.Isengard Industries - Sovereign mass production of precision-strike and counter-drone systems.
Team: Co-founder Francisco Serra-Martins previously founded drone-maker Terminal Autonomy (Stanford); joined by a former Australian Army special-warfare officer.Greypoint Industries - Soldier-deployable hardware to detect, geolocate and classify battlefield signals.
Team: A Canadian Army infanteer plus General Dynamics systems engineers.Vernius Systems - Mass-deployable radar for air defense.
Team: Repeat founders behind Sano and Auctify; engineering out of Defence Tech for Ukraine and Huawei.GUILD - AI-native defense contractor that wins and executes government manufacturing contracts.
Team: Ex-Morgan Stanley technologists; Columbia and Duke.Exosat - Satellites with zero U.S.-origin content, launchable from any nation, at a tenth of the cost.
Team: Founder was previously CEO of space-hardware startup Aethero.
2. Robots for Physical Labor
Agency Tool Company - Reliable infrastructure for robotics.
Team: Jack Morrison and Davis Foster co-founded Scythe Robotics (autonomous landscaping, sold to ASI); Morrison earlier co-founded Replica Labs (sold to Occipital), and Foster is a Thiel Fellow.Cosmic Robotics - Physical AI that builds solar farms and data centers today.
Team: Engineers from Relativity Space, SpaceX, Built Robotics, Autodesk Research and NASA JPL.Shiraz AI - Robots that learn on the job.
Team: CEO Navid Aghasadeghi was a senior staff roboticist at Boston Dynamics and principal robotics engineer at Rethink Robotics.Tensr - Fully autonomous robotic factories, from humanoid platforms to ISS-bound hardware.
Team: The Berkeley AI Racing Tech crew - BAIR researchers and autonomous race-car roboticists.Neuron Industries - AI-programmable PLCs for industrial automation.
Team: CEO led electrical engineering at Freeform; CTO founded WorkIPO.Grip - Robots for waste sorting and manipulation.
Team: ETH Zürich; founding engineers of URSA Mining and AMZ Racing’s driverless team.6thSense - A tactile sensing layer so manipulation models can feel contact, force and slip, not just see.
Team: Product and engineering leads from Skool, DoorDash and Amazon; Georgia Tech.Manifold - Fully autonomous warehouse picking, priced by the pick, live in warehouses today.
Team: Caltech and Penn researchers; a warehouse operator plus Balyasny and Starwood alumni.Salem Robotics - Robots that replace workers in hazardous spaces.
Team: UT Austin robotics researchers out of Los Alamos National Laboratory.Hebbian Robotics - APIs that verify data quality for robotics model training.
Team: Ex-Jane Street engineer; a former deputy head of applied research at AI Singapore.
3. AI Infrastructure - Inference, Evals & Training Data
rekursiv.ai - Teams of AI scientists that run experiments and create new knowledge.
Team: Two research scientists from Luma AI and Google/DeepMind (VideoPoet and TensorFlow Probability lineage).Prodigy Research - Training the best foundation model for quantitative finance.
Team: CEO was a senior researcher at Google DeepMind and a Jane Street quant.OneTriangle - KV-cache transfer tech that cuts inference cost ~20% and latency ~40%.
Team: MIT; CTO is a CSAIL researcher (Muon optimizer under Jacob Andreas), CEO did a stint in HFT at Virtu.OpenRelay - Distributed GPU cloud for production inference, up to 90% cheaper than the hyperscalers.
Team: Infra engineers from Voltage Park, TensorDock, Lightning AI and AWS.Moving Atoms - World models to test and train robot policies without the robot.
Team: Oxford; CEO built TikTok’s video recommendation algorithm.Experiential Labs - Turns your frontier-model traffic into a world model, then trains a small model you own.
Team: Staff research scientists from Waabi; a founding AutoGPT engineer.Touchmark - A market for future inference capacity.
Team: Co-founders are from Citadel Securities and Revolut.CoArena - Open-source computer-use agent at 82% on OSWorld.
Team: Purdue CS grads (Columbia and Stanford master’s); one an ex-Microsoft vision engineer.Markov - Sells expert computer-use data to frontier labs - 33k+ hours sold, 200k+ dataset downloads.
Team: Emergent Ventures and Bagel Fund grantees; ex-Sarvam AI.
4. Semiconductors, Compute & Hard Tech
Baud - Custom AI hardware and dev platform to train and serve frontier models.
Team: Chief hardware architect was a senior ASIC engineer at NVIDIA and on the technical staff at Enfabrica.Applied Electrodynamics - Sensors that perceive the full electromagnetic spectrum, not just visible light.
Team: The hardware team behind Humane’s Ai Pin (later HP IQ), with Apple iPhone hardware pedigree.Atomarine - Floating data centers on barges, anchored offshore and powered by nuclear ships alongside.
Team: An MIT nuclear science & engineering PhD and an MIT Sloan / ex-Arrowstreet Capital operator.Mass Magnetics - Recycled rare-earth scrap into American-made, DFARS-compliant permanent magnets.
Team: CTO from Draper (MIT) and Columbia Formula Racing.Dipole Labs - High-speed optical switches for AI and quantum infrastructure.
Team: Harvard postdocs; ETH Zürich and EPFL PhDs.Kara - High-purity lab-grown diamond wafers that move heat 5x better than copper.
Team: Berkeley; a former diamond trader plus Berkeley Lab researchers.83 Sciences - A materials-discovery engine built on the 90% of experimental data that never gets published.
Team: An MIT materials-chemistry PhD plus ex-BCG operators (one a principal); Harvard, Stanford.hardware intelligence - End-to-end, agent-native toolchain for chip design.
Team: Ex-Google engineer plus a Georgia Tech hardware-acceleration PhD.Standard Machines - Environments where AI can learn to design chips.
Team: Founder was previously at Apple.Synapse Semiconductor - Chips for environments humans can’t reach.
Team: A Duke engineering professor and a researcher from her lab.
5. Materials, Chemicals & Energy
Rise Reforming - Localized chemical production from biogas, to de-risk a centralized, fossil-dependent U.S. chemical industry.
Team: University of Chicago molecular-engineering researchers (Patel Group); a 776 Foundation fellow.Rasyn - Foundational AI models for chemistry, starting with the ~10-ingredient formulations behind datacenter coolant, GPU thermal paste, paint and glue.
Team: A Caltech computational chemist (Arnold Lab); researchers from NASA JPL and Biogen.Edviro - AI that operates energy infrastructure.
Team: Two 19-year-old UCSB founders; CEO was in OpenAI’s ChatGPT Lab program, CTO did a stint at RTX.Meteoric - Drones that clear clouds over solar farms - and, eventually, weaken severe storms and hurricanes.
Team: Cambridge; a researcher out of the Centre for Climate Repair.Ultrasonium - Shaping the future of metals manufacturing.
Team: MIT doctoral students; Argonne National Laboratory.ProvenMetal - Fast-turn, American-made PCBs. T
eam: Trinity College Dublin; second company from the Syncra founders.
6. Fintech & Insurance, Rebuilt Around a Model
Florin - Full-stack insurance carrier where a model does the underwriting — reading ACORD forms, then investigating the risk from satellite imagery, permits and public records.
Team: Founders from Tesla Autopilot, Boeing flight test, AWS and Google.PRINCEPS - Purpose-built insurer for the compute buildout: SLA, GPU residual value and outage risk.
Team: Oxford Union officers plus an MIT fluid-mechanics researcher.Stoa - Pricing and trading infrastructure for GPU hardware and other AI-infra assets.
Team: An ex-Citi rates-vol trader (Dartmouth) and a quant developer from Uniper; Cornell, UIUC.Syndo - Credit and lending, rebuilt with AI.
Team: CEO traded quant at Squarepoint, with earlier stints at Citadel Securities and IMC; CTO ex-Goldman quant strategist and Amazon.Levocred - AI agents inside credit funds and banks; ~$1B in receivables running through the platform.
Team: CEO was a quant researcher at Edge Focus Partners (and briefly Morgan Stanley), Berkeley MFE; CTO ex-Edge Focus and Samsung R&D.TovenAI - AI compliance agents for institutional trading firms.
Team: Ex-Meta ML engineer plus a Citadel quant research engineer; Stanford.Agentcard - Debit cards for AI agents.
Team: Karen Serfaty previously founded Atlas (acquired by Remote) and Palabra.The Billow AI - AI-native accounting firm; month-end close in minutes.
Team: Founder sold Opaper; joined by a repeat YC founder from Finnix (W22) and ex-Bloomberg.Last Accounting Company - “Never worry about accounting again.”
Team: The Token Terminal data team; Aalto University, Finland.
7. Vertical AI — Law, Healthcare & Government
Erinys - Everything needed to launch and scale an AI-native law firm: intake, back office, client acquisition.
Team: University of Maryland founding trio; ex-Barclays.Helios Law - Plaintiff-side litigation firm with a custom-built AI back office.
Team: Managing partner is a Harvard Law grad who clerked at the Colorado State Public Defender and practiced at Burns Charest.Locke - AI agents that help companies and governments work together, powering an AI-native government-affairs firm.
Team: Founder worked in the Biden-Harris White House drug-policy office and at the DNC.Chromie - An operating system for government contracting.
Team: Ex-Google, Plaid, Amazon and LinkedIn engineers; Georgia Tech and Maryland.Radley - An AI-native radiology practice.
Team: CTO was VP of software engineering at Carbon Health; MIT.Omanta - A personalized research lab for patients who have exhausted standard options.
Team: Broad Institute and Harvard cancer-program researchers.Prescience - Preventive, continuous care instead of catastrophe-driven medicine.
Team: Harvard Medical School and Harvard; co-founders of ICOR Therapeutics and Qurios (acquired), respectively.Care GP - Out-of-the-box AI agents for GP clinics.
Team: Forbes 30 Under 30 founder; ex-Latch VP International; Oxford.
8. Dev Tools & Agent Infrastructure
Dock - A multiplayer workspace where agents and humans share the same docs and sheets, and agents keep working when you close the tab.
Team: Mike Molinet co-founded Branch (mobile linking) and Thena.Mentlio - Engineering-intelligence platform for the AI-coding era - Cursor, Claude Code, Codex, Gemini.
Team: Caltech; CEO was an Anthropic campus lead, CTO a founding engineer at OpenRecovery.Bullet - A coding agent built for speed.
Team: Yale CS/econ; a summer on AppLovin’s technical staff.Prized - A cloud dev environment that feels local on your Mac.
Team: Both were engineers at Gander (YC F24, acquired); CEO later at Suno. Stanford, Florida.Executor - Open-source tool gateway.
Team: Founder was a software engineer at Vercel and Dosu.OneCLI - Open-source agent harness where credentials are injected at the network layer, never held by the agent.
Team: Founders of ChartDB; ex-Aqua Security and Argon (acquired by Aqua).Inkbox - Persistent identities (email, phone, iMessage) for AI agents.
Team: The Empallo founding team; MIT and Northeastern.machine0 - “AWS for agents.”
Team: Founder co-founded Upflow, where he was CTPO.Context.dev - One API for every piece of web context an agent needs.
Team: Founder sold Essense.io to Optic; was a principal engineer at Sunrun.
9. Cybersecurity
Fabraix - AI red-teaming agents that continuously probe customer-facing AI; its product Nyx has found vulnerabilities in agents at dozens of Fortune 500s and tops the AgentHarm benchmark.
Team: Ex-Meta engineer (Oxford); a former Monzo fraud data scientist (UCL).Trident - Autonomous offensive security agents — “the best defense is offense.”
Team: CEO is a competitive CTF player and ex-Wealthsimple engineer (brief stint on Tesla’s offensive security team).Nebula Security - “The AI-native cybersecurity company.”
Team: UC Riverside security PhDs; ex-Microsoft and Samsung Research America security researchers, plus a Zellic researcher.Caution - Verifiable confidential compute — enclaves, attestation and cross-cloud portability, fully open source.
Team: The Distrust team; ex-OpenZeppelin blockchain-security lead and Ledn head of security.Verdict Machine - One model for malicious-transaction prevention, continuous cyber diligence and security posture across an institution’s on-chain environment.
Team: The team that ran blockchain security at Check Point; CEO is a former YC teaching assistant and keyTango founder.Traceforce - Visibility and control over AI apps (ChatGPT, Claude) on every device, including how they’re wired to data via MCP.
Team: Co-founder/CTO was a senior engineer at LinkedIn, Clumio and Microsoft; UC Berkeley.
10. Biotech & Bio-Compute
WonderTx - Extrapolative AI to design first-in-class drugs.
Team: CEO Abraham Heifets co-founded and ran Atomwise.TareBio - Vaccines for any cancer or infection.
Team: Founder is an MD-PhD (UCLA-Caltech MSTP) out of MIT’s Koch Institute - the Bhatia and Wittrup labs.Gamgee - AI-first platform for personalized mRNA cancer vaccines, starting with dogs.
Team: Founder is a former senior data scientist and ML consultant (Australia).Molagri - Resistance-free pesticides.
Team: Two University of Toronto PhD candidates.Frontier Computing - Grows scalable biological brains as an ML training substrate.
Team: Cambridge; ex-Mercatus Emergent Ventures fellow.Otis Labs - Neurotech for healthier herds.
Team: Stanford EE and Harvard Medical School research fellows.
11. Consumer, Media & Everything Else
Familiar - One model that does the voice, the lips and the scene together for film translation into 30 languages.
Team: CTO founded CineLingo; researchers from Adobe and Tavus.RonanRX - Full-stack pharma company; licensed in 33 states in 10 weeks, growing 50% week over week.
Team: CEO Lloyd Armbrust founded OwnLocal and Armbrust American.MOCHI.TV - Mobile-first vertical anime shorts, new shows daily, made with AI.
Team: Repeat consumer founders; ex-Amazon.Marble - AI-native operating system for restaurants, cafes and bars.
Team: Ex-Goldman Sachs analyst plus a Bloomberg engineer; Michigan.screenpipe - Open-source, on-device screen memory that turns how you work into searchable SOPs and agents.
Team: Founder previously built Mediar; large open-source following.Touchy - An AI voice assistant for iPhone that understands the world around you.
Team: Berkeley CS61C head TAs and lecturers; ex-SkyPilot, ex-Google DeepMind.Catapult - “Building the training ground for AGI, one game at a time.”
Team: UCLA researchers; ex-Scale AI and MIT.
This is 77 of ~250. The batch keeps going: another wave of AI-native accounting firms, ERP-agent deployers, GPU-market plays, and vertical copilots for every regulated industry you can name, plus the ones still in stealth with nothing but a landing page and a Palantir-forward-deployed founder.
Want every company? Gravity's full Y Combinator Summer 2026 dataset, all ~250 companies and 500+ founders, with prior companies, schools, and roles is here: [link].
If a batch like this is useful, forward it to someone who’d want it, and subscribe so the next one lands in your inbox.
Stay Stealthy,
Drake
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Stealth Startup Spy is a data-driven newsletter for investors, journalists and tech enthusiasts interested in uncovering the next big move for key talent, real-time stealth company launches and technology advancements not in plain sight. We leverage the technology built at Gravity to shine a light on the hidden world of stealth startups.