Horizon3 has raised a $250 million Series E co-led by NightDragon and NEA at a stated valuation above $2 billion, up from $650 million at its June 2025 Series D.
The round brings total funding to $428.5 million across six rounds since 2020, and adds strategic investors including Singapore's EDBI, defence contractor SAIC and Qualcomm Ventures.
Against claimed recurring revenue approaching $100 million, the valuation implies a multiple of roughly 20 times, on figures the company has not had independently audited.
The platform's core proposition is autonomous attacks on live production systems that break nothing, a claim resting on a stated record of 310,000 tests without disruption.
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