GreatHorn

GreatHorn is a technology company.

Active

Updated: Dec 9, 2025 ·

Recent News & Mentions

Jun 1, 2019FundingGreatHorn - Series B Jun 1, 2017FundingGreatHorn - Series A Mar 1, 2016FundingGreatHorn - Seed

Financial History

GreatHorn has raised $21.0M across 3 funding rounds. Most recently, it raised $13.0M Series B in June 2019.

Total Raised

$21.0M

Valuation

N/A

Funding Rounds Raised

Date	Round	Other Investors
Jun 1, 2019	$13.0M Series B	Amasia, Andreessen Horowitz, FJ Labs, Foundry Group, Fuse, Red Tree Venture Capital, RRE Ventures, Uncork Capital, Xfund, Anna Patterson, Evan Cheng, Patrick S. Chung
Jun 1, 2017	$6.0M Series A	Amasia, Andreessen Horowitz, FJ Labs, Foundry Group, Fuse, Red Tree Venture Capital, RRE Ventures, Uncork Capital, Xfund, Anna Patterson, Evan Cheng, Patrick S. Chung
Mar 1, 2016	$2.0M Seed	Amasia, Andreessen Horowitz, Collaborative Seed & Growth Partners, FJ Labs, Foundry Group, Fuse, General Catalyst, Hyperplane Venture Capital, Red Tree Venture Capital, RRE Ventures, Sandbox Industries, TBD Angels, Uncork Capital, Xfund, Anna Patterson, Evan Cheng, Patrick S. Chung

Financial History

GreatHorn has raised $21.0M across 3 funding rounds.

Total Raised

$21.0M

Valuation

N/A

Deep Dive

GreatHorn is a cloud-native email security company that builds an integrated platform to protect enterprises from phishing, business email compromise, social engineering, and zero-day email threats. It serves organizations using cloud email services like Office 365 and G Suite, primarily targeting sectors such as finance and education. GreatHorn’s platform combines advanced machine learning threat detection, user engagement through contextual education, and incident response capabilities to reduce email-related risks and improve security team efficiency. The company has demonstrated growth momentum by raising over $22 million in funding and serving Global 2000 companies with rapid deployment and high-impact protection[1][2][6].

Founded in 2015 and headquartered in Waltham, Massachusetts, GreatHorn was created to address the limitations of legacy email security gateways that were not designed for cloud-first environments. The founders leveraged their expertise in cybersecurity and data science to build a platform that continuously adapts to each organization’s unique communication patterns, enabling precise detection of anomalous and malicious emails. Early traction came from enterprises seeking modern, cloud-native solutions that integrate threat detection with user education and automated incident response, setting GreatHorn apart in the evolving email security market[1][2][4].

Core Differentiators

Cloud-native architecture: Designed specifically for cloud email platforms like Office 365 and G Suite, enabling rapid deployment (under 5 minutes) without MX record changes or mail routing disruptions[2][3][6].
Layered security approach: Combines adaptive threat detection at the perimeter, real-time user education at the point of engagement, and incident response/remediation after exposure to minimize risk comprehensively[3].
Machine learning and data science: Uses proprietary datasets from analyzing hundreds of millions of threats to continuously learn legitimate communication patterns and detect sophisticated phishing and impersonation attacks[2][3].
User empowerment: Provides contextual warnings and smart banners to employees, enhancing their ability to identify threats beyond automated detection alone[2][3].
Integrated incident response: Enables security teams to quickly identify, bulk remove, and remediate threats across user mailboxes, improving operational efficiency[3][6].

Role in the Broader Tech Landscape

GreatHorn rides the critical trend of cloud migration and the increasing sophistication of email-based cyber threats, such as spear phishing and business email compromise. As organizations shift to cloud email platforms, legacy security tools fall short, creating a market need for cloud-native, adaptive solutions. The timing is crucial given the rise in targeted email attacks and the growing regulatory and operational emphasis on cybersecurity risk management. GreatHorn influences the ecosystem by advancing email security from simple threat blocking to a risk management discipline that integrates technology with human factors, thereby reducing breach risks and improving organizational resilience[2][3][6].

Quick Take & Future Outlook

Looking ahead, GreatHorn is positioned to expand its influence by deepening integrations with cloud platforms and security orchestration tools, enhancing AI-driven threat intelligence, and broadening its user engagement capabilities. Trends such as increased remote work, cloud adoption, and regulatory scrutiny on data breaches will likely drive demand for sophisticated, automated email security solutions. GreatHorn’s emphasis on layered protection and risk management suggests it will continue evolving as a critical player in securing cloud communications, potentially expanding into adjacent areas of enterprise security and threat response[2][3][6]. Its ability to reduce email risk by up to 99% as reported by customers underscores its growing impact in the cybersecurity landscape.

Sources

Frequently Asked Questions

How much funding has GreatHorn raised?

GreatHorn has raised $21.0M in total across 3 funding rounds.

Who are GreatHorn's investors?

GreatHorn's investors include Amasia, Andreessen Horowitz, FJ Labs, Foundry Group, Fuse, Red Tree Venture Capital, RRE Ventures, Uncork Capital, Xfund, Anna Patterson, Evan Cheng, Patrick S. Chung.

Frequently Asked Questions

How much funding has GreatHorn raised?

GreatHorn has raised $21.0M in total across 3 funding rounds.

Core Differentiators

Cloud-native architecture: Designed specifically for cloud email platforms like Office 365 and G Suite, enabling rapid deployment (under 5 minutes) without MX record changes or mail routing disruptions[2][3][6].
Layered security approach: Combines adaptive threat detection at the perimeter, real-time user education at the point of engagement, and incident response/remediation after exposure to minimize risk comprehensively[3].
Machine learning and data science: Uses proprietary datasets from analyzing hundreds of millions of threats to continuously learn legitimate communication patterns and detect sophisticated phishing and impersonation attacks[2][3].
User empowerment: Provides contextual warnings and smart banners to employees, enhancing their ability to identify threats beyond automated detection alone[2][3].
Integrated incident response: Enables security teams to quickly identify, bulk remove, and remediate threats across user mailboxes, improving operational efficiency[3][6].