Major U.S. Startup Funding Deals in 2025
The startup funding landscape has witnessed significant activity in 2025, with several remarkable investment rounds surpassing the $100 million mark. Below is a summary of the most substantial funding deals reported in the past week, showcasing the resilience of venture capital even in fluctuating market conditions.
Highlighting the Top 10 Funding Rounds
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OpenAI – $40 Billion
In a groundbreaking announcement, OpenAI secured a monumental $40 billion investment led by SoftBank. This investment is heralded as the largest venture capital deal in history. The funding structure involves SoftBank mobilizing a syndicate of co-investors to contribute $10 billion, while the remaining $30 billion will be funded directly, partially through debt. Following restructuring of OpenAI’s for-profit subsidiary, the company could potentially achieve a post-money valuation of $300 billion.
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Plaid – $575 Million
Fintech innovator Plaid raised $575 million in a significant funding round led by Franklin Templeton, bringing its total valuation to $6.1 billion. The funds will be allocated towards fulfilling employee tax obligations related to share conversions and providing liquidity through a tender offer. Notably, Plaid’s previous $5.3 billion acquisition deal with Visa was halted due to regulatory challenges.
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Silicon Ranch – $500 Million
Nashville’s Silicon Ranch secured $500 million from AIP Management, a European infrastructure investor. This investment is a strategic move, anticipating the rising electricity demands in the U.S. The company operates solar and battery projects and has accumulated over $2 billion in funding since its inception in 2011.
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Runway – $308 Million
The AI video startup Runway has raised $308 million, effectively doubling its valuation from just two years ago to over $3 billion as led by General Atlantic. The company plans to enhance its offerings, particularly with its newly unveiled Gen-4 AI model that facilitates video creation using text prompts and images. Founded in 2018, Runway has received more than $540 million in total funding.
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AIRNA – $155 Million
AIRNA, a biotech company based in Cambridge, Massachusetts, closed a $155 million Series B round led by Forbion Capital Partners and Venrock Healthcare. These funds will accelerate clinical trials for treatments targeting alpha-1 antitrypsin deficiency and support the development of RNA editing therapies. AIRNA has raised a total of $245 million since its founding in 2021.
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Atsena Therapeutics – $150 Million
Also securing $150 million is Atsena Therapeutics, a Durham, North Carolina-based company focused on gene therapy for eye diseases. The Series C funding, led by Bain Capital, will propel its efforts in treating X-linked retinoschisis and fortifying its preclinical pipeline. Since its inception in 2019, Atsena has raised nearly $238 million.
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SandboxAQ – $150 Million
SandboxAQ, a startup emerging from Alphabet with a focus on AI and quantum computing, raised an additional $150 million in its Series E financing round, counting Google and Nvidia among its investors. The firm is exploring AI’s implications for quantum technology, having previously raised $300 million at a $5.6 billion valuation earlier this year. Total funding for SandboxAQ exceeds $950 million since its establishment.
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Temporal Technologies – $146 Million
Temporal Technologies, based in Seattle, accomplished a $146 million Series C funding, achieving a valuation of $1.7 billion. This investment, led by Tiger Global Management, is aimed at enhancing cloud products and advancing AI development. Temporal has raised $350 million since its inception in 2019.
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RayThera – $110 Million
San Diego’s RayThera, focusing on immunology innovations, completed its first round of financing, gaining $110 million through a Series A round co-led by Foresite Capital and OrbiMed, as noted in Crunchbase data.
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Neurona Therapeutics – $102 Million
Neurona Therapeutics, a South San Francisco company dedicated to developing regenerative therapies for neurological disorders, raised $102 million in funding, with Fidelity Management & Research Co. among the investors. Founded in 2008, Neurona has amassed a total of $426 million to date.
International Highlights
In addition to the impressive U.S. funding rounds, the week saw significant global activity. London’s Isomorphic Labs, a company focusing on AI applications in drug development, raised $600 million in its first external funding round led by Thrive Capital and supported by Google Ventures.
Funding Round Methodology
This report covers the largest disclosed funding rounds by U.S.-based companies for the week of March 29 to April 4, 2025, using data sourced from the Crunchbase database. Each round is tracked for accuracy, although some funding announcements may face delays in reporting.