On August 5, 2025, SentinelOne signed a definitive agreement to acquire Prompt Security—an AI-security startup specializing in real-time runtime protection—in a transaction involving both cash and stock.
The acquisition will expand SentinelOne’s Singularity platform with capabilities to detect and prevent AI-specific threats such as prompt injection and data leakage. The deal is expected to close in SentinelOne’s third quarter of fiscal year 2026, likely by October or November, pending regulatory approvals and customary closing conditions.
This strategic move marks a pivotal shift in enterprise cybersecurity. Whereas SentinelOne has long focused on “AI for security,” leveraging artificial intelligence to safeguard systems, the acquisition of Prompt Security signals a new priority: “security for AI.”
As organizations embrace generative and agentic AI, ensuring safe and controlled usage of these tools becomes critical. Integrating Prompt Security’s real-time observability and enforcement mechanisms, SentinelOne aims to enable secure AI adoption at scale across the enterprise.
Acquisition Details and Rationale
Reports place the valuation of SentinelOne’s acquisition of Prompt Security between $250 million and $300 million, a figure that far exceeds the relatively modest funding the startup had raised previously. While the companies have not formally disclosed the financial terms, industry estimates place the deal at roughly $250 million.
From a strategic perspective, the acquisition is a strong fit for SentinelOne’s vision. Prompt Security brings real-time visibility into AI tool usage, policy-based enforcement capabilities, and protection against AI-specific threats such as prompt injection and data leakage. These features are designed to integrate with SentinelOne’s Singularity platform, enhancing its ability to secure generative and agentic AI adoption in real time.
“SentinelOne pioneered the use of AI in cybersecurity, disrupting core categories like endpoint protection, cloud security, and data/SIEM. Now, we’re poised to set the standard for how AI itself is secured,” said Tomer Weingarten, CEO of SentinelOne. “The combined capabilities of SentinelOne and Prompt will enable organizations to embrace AI with confidence and reap the rewards it can deliver, while managing the array of risks it opens at scale. It’s a bold step forward in our strategy to be the world’s definitive AI Security company and will redefine what it means to protect the modern enterprise.”
Itamar Golan, CEO and Co-Founder, Prompt Security, agreed with the deal’s potential synergies. “Prompt brings AI-native guardrails that understand model behavior, and SentinelOne brings deep visibility and automated response across endpoints, cloud, and identity,” he said, “Together we let enterprises see, stop, sanitize, educate, and govern AI use in real time so they can innovate with confidence while minimizing risk. Together we are the go-to accelerator for safe AI adoption.”
By combining Prompt Security’s runtime AI defense capabilities with its existing AI-powered endpoint and cloud infrastructure, SentinelOne is reinforcing a shift from using AI for security to enabling security for AI. This approach positions the Singularity platform as a more comprehensive and future-ready cybersecurity solution.
What Prompt Security Brings to the Table
Prompt Security adds comprehensive visibility across enterprise AI usage. Its tools track activity in browsers, desktop applications, APIs, terminals, integrated development environments, and custom large language models. The platform provides detailed inventories, logging, and compliance support, giving security teams real-time insight into AI operations.
Policy control is another key strength. Organizations can apply data redaction and tokenization, filter or block risky prompts, and provide inline guidance to users as they interact with AI systems. These controls help prevent misuse while maintaining productivity.
The platform also includes robust protection features. It defends against prompt injection, jailbreak attempts, sensitive data exfiltration, and exposure of developer secrets. It can even mitigate financial attacks on AI-driven systems, sometimes referred to as “denial of wallet” attacks.
A standout component is the MCP Gateway, which dynamically scores risk for AI agents and servers and applies mediation as needed. This layer ensures that AI-driven workflows remain secure without disrupting legitimate operations.
Strategic Implications
The acquisition marks a broader shift in enterprise cybersecurity. Companies are moving from using AI to strengthen security to actively securing AI itself within their systems. By integrating Prompt Security’s capabilities, SentinelOne positions its Singularity platform as a leader in AI-era cyber defense, offering organizations the tools to safely deploy generative and agentic AI at scale.
The deal also reflects a wider consolidation trend in AI-focused cybersecurity. Smaller startups often face high costs to develop advanced AI defenses, making them prime targets for acquisition by larger platforms. Similar moves in the industry include Google’s $32 billion acquisition of Wiz and Palo Alto Networks’ integration of Protect AI. SentinelOne’s move signals both strategic growth and the increasing value of runtime AI protection in the evolving cybersecurity landscape.
Sector Context and Market Trends
The convergence of cybersecurity and AI is reshaping industry mergers and acquisitions. Companies are increasingly using acquisitions as the fastest route to integrate AI-native capabilities, gaining both technology and expertise in a competitive market. This trend reflects the growing importance of AI in protecting complex enterprise environments.
SentinelOne’s acquisition of Prompt Security aligns closely with these dynamics. AI is driving both platform consolidation and expansion as organizations face escalating cyber threats and stricter compliance requirements. By absorbing specialized AI security startups, larger platforms can accelerate innovation while providing comprehensive, enterprise-ready solutions. The deal demonstrates how AI is not only transforming security operations but also influencing strategic decision-making across the cybersecurity sector.
Outlook and Future Trends
Once fully integrated, SentinelOne’s acquisition of Prompt Security could give businesses greater confidence in deploying generative AI and intelligent agents. Organizations may adopt these technologies more widely while maintaining a strong security posture across endpoints, applications, and cloud environments.
The deal also raises the bar for competitors. Other cybersecurity platforms will likely need to embed runtime AI protection into their offerings to remain relevant, creating a new standard for enterprise AI security.
Looking ahead, deeper collaboration between AI providers and security firms is expected. Companies will work to build native guardrails that prevent AI-specific threats, such as prompt injection, model misuse, or unauthorized AI deployments often referred to as “shadow AI.” This trend points toward a more secure and accountable AI ecosystem across enterprises.
Securing the AI layer
SentinelOne’s acquisition of Prompt Security represents a pivotal shift in enterprise cybersecurity. The focus is moving from using AI to protect systems to embedding security directly within AI operations. This transition establishes runtime AI defense as a critical component for safely deploying generative and agentic AI at scale.
