Backed by General Catalyst and Rally Ventures, Ostra extends its Series A to $9.5M to scale its platform, grow its team, and integrate Blackwell Security
MINNEAPOLIS, Aug. 7, 2025 /PRNewswire-PRWeb/ -- Ostra Security, a leading managed security provider, today announced a Series A Extension that brings the total funding round to $9.5 million, co-led by General Catalyst and Rally Ventures with participation from long-time Ostra investment partner Jeff Cowan at CapitalFour. The new capital will accelerate hiring, deepen technical capabilities, and expand the tailored service model already resonating with businesses under pressure to secure their operations without adding internal burden.
In a move that strengthens both scale and capabilities, Ostra also announced the acquisition of Blackwell Security, a cybersecurity company known for its advanced managed detection and response (MDR) platform and deep industry expertise. The integration of Blackwell's managed XDR platform, Pulse, with Ostra's best-in-class managed security services will deliver broad protection to better support businesses at every stage.
Ostra and Blackwell are joining forces to address a critical market need: organizations are overwhelmed by security complexity, under-resourced internally, and facing increased scrutiny from stakeholders. This integration creates a single, outcome-driven solution that enables businesses to strengthen defenses while keeping focus on growth.
"We're not just closing today's security gaps. We're building the future of how growing companies protect themselves," said Andrew Tewksbury, CEO of Ostra Security. "Bringing Blackwell's leading MDR platform together with our high-touch model means our customers will navigate risk with unprecedented clarity and control. It's a major step toward delivering the next generation of outcome-driven managed security."
The expanded funding underscores strong investor confidence in Ostra's vision and its ability to deliver measurable outcomes in a market that has long struggled with bloated stacks, wasted spend, and underperformance.
"Cybersecurity is moving beyond buying tools and hoping they work. Ostra's approach delivers real, measurable outcomes that give IT leaders and boards confidence in their security posture," said Mark Crane, Partner at General Catalyst. "The addition of Blackwell strengthens an already impressive platform and team, and we're proud to back a company so deeply committed to delivering results for its customers."
About Ostra Security
Ostra Security replaces tool sprawl and costly shelfware with hands-on, white-glove protection that adapts to each client's unique environment and needs. Ostra Security goes beyond alerts to own real outcomes, delivering measurable risk reduction, board-ready reporting, and a true partnership that feels like an extension of your team.
Media Contact
Rachel Subasic, Ostra Security, 1 (952) 995-7450, [email protected], https://www.ostra.net/
SOURCE Ostra Security
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