Cloud Infrastructure Security Startup Upwind Secures $400 Million Series C at $3.8 Billion Valuation

Upwind, a San Francisco-based cybersecurity startup that leverages artificial intelligence to secure cloud infrastructure, has successfully raised a massive $400 million Series C financing round. The new investment values the four-year-old company at $3.8 billion. The funding round was led by Bessemer Venture Partners, with additional participation from a robust roster of existing backers, including Greylock Partners and Craft Ventures.

The milestone comes just nine months after Upwind closed its previous financing event—a $250 million round that valued the startup at $1.5 billion in January 2026. The rapid ascent in valuation highlights the intense investor appetite for advanced cloud security platforms as organizations globally struggle to protect complex digital environments against sophisticated, AI-driven threats.

However, the path to closing this latest massive round was not entirely straightforward. According to a person familiar with the matter who spoke on the condition of anonymity, the fresh funding had been in the works for months and nearly fell apart entirely due to an acquisition attempt. Datadog, a publicly traded titan in the software observability space that sells tools for monitoring application performance and runtime behavior, made a play to acquire Upwind outright.

Ultimately, the acquisition talks broke down because Datadog’s buyout proposal did not offer a meaningful premium above the $3.8 billion valuation already established by the venture capital investors. Facing the choice between a near-term exit at that price point and remaining independent, Upwind leadership opted to turn down the acquisition offer and stick to its long-term growth trajectory.

The decision to walk away underscores substantial confidence within the startup’s executive ranks. By rebuffing Datadog, Upwind’s leadership is effectively betting that the company’s continued independent expansion will yield an enterprise value well north of $3.8 billion in the coming years. Nevertheless, industry observers note that given the current dry market for initial public offerings among cybersecurity firms, an eventual acquisition remains one of the most statistically probable exit strategies for high-flying startups of this caliber. According to sources close to the company, Upwind continues to attract ongoing acquisition interest from other industry players.

Founded by serial entrepreneur Amiram Shachar—who previously built and successfully exited cloud spend management startup Spot.io to NetApp for $450 million—Upwind has carved out a distinct niche by focusing on what it calls "runtime" security. Unlike traditional static security tools that scan code repositories or configurations before deployment, Upwind’s platform monitors active, running cloud services in real time. This approach allows the system to instantly detect, alert, and actively remediate attacks, vulnerabilities, and misconfigurations as they happen in live production environments.

This operational philosophy has resonated strongly with enterprise buyers, fueling staggering financial growth. Upwind has been consistently adding between $20 million and $30 million in annualized recurring revenue (ARR) every single quarter. According to financial details shared by an individual familiar with the startup’s books, Upwind is projected to close the year at approximately $90 million in ARR.

At a $3.8 billion valuation, both the venture capital syndicate and Datadog were pricing the startup at more than 40 times its forecast ARR. While a 40x multiple represents a lofty valuation by historical market standards, it is notable for being significantly lower than some of its peers in the current hyper-competitive cybersecurity landscape. For context, Cyera, another exceptionally fast-growing data security startup, was reported earlier this year to be eyeing a staggering $12 billion valuation at an 80x ARR multiple despite operating at a loss.

The massive capital injection into Upwind aligns with broader macroeconomic and sectoral trends shifting across the enterprise software market. Tomasz Tunguz, a general partner at Theory Ventures and a prominent venture capital commentator, recently noted in a widely read industry analysis that cybersecurity is rapidly materializing as the third major wave of artificial intelligence software that corporate buyers are willing to invest heavily in, following closely behind AI-driven coding assistants and customer support automation tools. As enterprises expand their cloud footprints and integrate more autonomous AI workloads, securing those dynamic systems has shifted from a discretionary line item to an absolute boardroom priority.

As Upwind absorbs its latest $400 million war chest, the company finds itself well-capitalized to scale its engineering teams, accelerate go-to-market strategies, and expand its footprint in the runtime cloud security market. Representatives for both Upwind and Datadog have been approached for comment regarding the aborted acquisition discussions and the details of the Series C funding round.