Biggest Startup Funding Rounds, 8 to 29 October 2026: Eight Deals, Sourced

Eight startups announced rounds of at least $50 million between 8 and 29 October 2026, totalling about $7.1 billion on the amounts announced or reported. Re:Build's $2.1 billion of new funding, announced on 27 October, is the largest. No Form D filing matched the announced amount for any round in this check, so each figure below is labelled as a company announcement or an outlet report.

Which startup rounds of at least $50 million were announced from 8 to 29 October 2026?

Eight rounds met the threshold in this window. Five were announced in company releases. Two rest only on outlet reports, and Sabi's round has a company release but a valuation that only outlets report. The table lists them by announcement date, with the company-stated post-money valuation where one was given.

Oratomic and Sabi fall outside the most recent week. They are included because the window runs from 8 October, and both rounds were announced inside it.

What did Re:Build, Tenstorrent and Kalshi announce?

These three are the largest rounds in the table. Each figure comes from the company's own announcement, and each is labelled as the company's claim.

Re:Build, based in Boston, announced on 27 October 2026 that it had secured $2.1 billion in new funding. General Catalyst and JPMorganChase's Strategic Investment Group led the capital, which the company says will expand its capacity to manufacture hard tech products. The company did not give a valuation in the material cited here.

Tenstorrent said on 19 October 2026 that it had closed $1.5 billion in Series E funding at a $6.2 billion post-money valuation. Trace Capital and Innovation X led the round, with participation from new and existing investors. Pulse 2.0 reported the same figures on 27 October.

Kalshi, a New York-based platform for trading contracts on real-world events, announced a $1 billion Series G at a $40 billion post-money valuation on 29 October. Wellington and Sequoia co-led the round. Crowdfund Insider reported the close on 30 October.

What did Flapping Airplanes, Bedrock Robotics and Dren Bio raise?

Outlets reported Flapping Airplanes' $1 billion. Bedrock Robotics announced $600 million, and Dren Bio announced a $350 million private financing. No company announcement for Flapping Airplanes was among the sources used, so its figure is an outlet report.

Flapping Airplanes' $1 billion Series A was reported on 21 October, and TradedVC reported the Index Ventures and Lux Capital co-lead on 22 October. The round funds research into making AI less costly to train and run. Our earlier note on the round is at /flapping-airplanes-series-a.

Bedrock Robotics announced a $600 million Series C at a $4.1 billion post-money valuation on 26 October. CapitalG and Emergence Capital co-led. A3 reported that Bessemer Venture Partners, Temasek and US Innovative Technology Fund were new investors. Our earlier coverage is at /bedrock-robotics-funding-series-c-600m.

Dren Bio, a privately held, clinical-stage biotechnology company in San Carlos, California, announced the closing of an oversubscribed $350 million private financing on 29 October. Juvia Group and Lightspeed Venture Partners co-led. The company's headline ties the money to advancing dibotatug toward commercialization.

What did Oratomic and Sabi raise, and who backed them?

Oratomic and Sabi are the two smallest rounds in the table. Oratomic is reported only by outlets in this check. Sabi has a company release, which is the basis for the round itself, and outlet reports; its $600 million valuation comes only from outlets.

Oratomic, a Pasadena-based quantum computing startup founded in 2025, raised a $475 million Series B. Pomegra reported that the round was announced on 8 October 2026. Dealroom listed six co-leads: ARCH Venture Partners, Spark Capital, Khosla Ventures, Index Ventures, General Catalyst and Bezos Expeditions. Pomegra gives the same six names.

Sabi, a Palo Alto company, announced a $50 million seed round led by Khosla Ventures on 9 October 2026. Accel, Initialized Capital, former OpenAI Chief Product Officer Kevin Weil, DST Global, Collaborative Fund and Ascend also participated. The company is building a baseball cap that converts a wearer's thoughts into text, according to AI Weekly.

What does a Form D check show for these rounds?

No Form D filing matched the announced amount for any round in this check. Filings for four of the rounds were not found, and filings for two more were not retrieved.

Kalshi, Flapping Airplanes, Bedrock Robotics and Dren Bio had no Form D for the October rounds in the search results for the period. A September 2026 Form D for Tenstorrent did not match the October Series E. Oratomic and Sabi are not covered by any SEC filing in this check, so their amounts rest on outlet and company reports. For a guide to reading the filing, see /form-d-startup-funding-explained.

How do the valuations compare with the round sizes?

Three rounds carry a company-stated post-money valuation. Dividing each round by its valuation gives the share of the company that the new money represents, if the round was all new equity.

The computed column is arithmetic on company-stated figures. It is not a disclosed ownership stake. It assumes that the valuation is post-money and that the whole round was new equity, which neither the releases nor the filings confirm. The gap between Tenstorrent's 24.2% and Kalshi's 2.5% shows how differently the three rounds were priced.

What's still unclear?

Several figures in this tracker are open. The main conflicts and gaps are below.

• Sabi's valuation. AI Weekly and daily.dev report $600 million. Pomegra lists the valuation as undisclosed. The figure is reported, not confirmed.
• Re:Build's instrument. The company calls the $2.1 billion "new funding" and gives no valuation. The material cited here does not say whether all of it is equity.
• Outlet-only rounds. Flapping Airplanes and Oratomic rest on outlet reports. Flapping's coverage describes its megakernel framework as a research effort, not a commercial product, and the capability claims are the company's own.
• Co-lead wording. Oratomic's co-lead list comes from outlets, not from a company release, and it names six firms.
• Form D coverage. No matching filing exists for the amounts in this check. Companies do not always file on the same timeline as their announcements, so a filing may appear later and change this table.
• Coverage window. The list is not a full ranking of October funding. It includes eight rounds of at least $50 million that met the sources' criteria, and it may omit larger rounds announced without the sources used here.