GreatHorn Raises $13 Million to Support Rapid Growth of its Email Security Platform

RRE Ventures and .406 Ventures Co-lead the Company’s Latest Round of Financing.

Waltham, MA – June 26, 2019 – GreatHorn, provider of the only email security platform that protects organizations before, during, and after an email attack, today announced it has closed a $13 million funding round co-led by RRE Ventures and .406 Ventures, with participation from existing investors including Techstars Ventures, V1.VC and Uncork Capital. On the heels of its third consecutive year of triple-digit revenue growth and rapid expansion into the enterprise market, GreatHorn plans to continue to build upon its position as the innovation leader in the email security space.

“RRE Ventures invests in passionate and tenacious teams that are building category-defining businesses,” said Raju Rishi, General Partner at RRE Ventures. “Despite decades of experience and billions of dollars spent, the email security industry is no closer to making email safe for businesses. By rethinking how we approach email security, GreatHorn has delivered a platform that comprehensively protects enterprises against the rising sophistication of today’s threats. We’re excited to support GreatHorn as the company continues to build upon its current innovation and grow in the enterprise space.”

As the only 100 percent cloud-native platform dedicated to comprehensive email threat protection, the GreatHorn Email Security threat detection and response platform safeguards organizations before, during, and after an email attack. Unlike legacy tools that rely on reactive threat detection methods and binary, perimeter-based analysis, GreatHorn secures enterprises from email threats at every vulnerable point – from inline pre-inbox analysis through to time of delivery, and uniquely, even post-delivery during incident response and continuous analysis – with integrated threat detection, protection, defense, and incident response.

By combining its industry-leading threat detection engine with in-the-moment user education and comprehensive incident response capabilities, GreatHorn’s email security platform shields businesses from business email compromise, credential theft attempts, business services spoofing, malware, ransomware, and other advanced social engineering-based phishing attacks.

“Since our initial investment in GreatHorn, we’ve witnessed how interest in the platform and its unique value proposition continues to explode,” said Greg Dracon, Partner at .406 Ventures. “With this additional investment, GreatHorn will be able to continue expanding its product leadership and accelerate its growth and penetration into the enterprise market.”

“With a fast-growing customer base and track record of best-in-class detection and innovation for today’s cloud-based email platforms, GreatHorn has changed the way the industry talks about email security,” said GreatHorn CEO Kevin O’Brien. “As we continue to meet customer demand and drive the market, we remain fundamentally interested in redefining email as a secure system for all users, and ensuring that organizations who have adopted cloud email platforms are not relying on outdated perimeter controls or simple user education to protect their most critical assets.”

About GreatHorn

GreatHorn safeguards cloud email from advanced threats such as individual and brand impersonations, credential theft attempts, malware, ransomware, and other advanced social engineering-based phishing attacks by protecting organizations before, during, and after an email attack. Through its proactive threat detection engine, in-the-moment user education, and robust incident response capabilities, GreatHorn frees security teams from time-consuming email security management while enabling them to respond to genuine threats faster than ever before. More information is available at

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