Three more cybersecurity startups announced funding rounds today, continuing an investment streak that sent the sector’s deal volume to a three-year high during the first half of 2025. 

Sublime Security Inc. and ConductorOne Inc. focus on protecting employee inboxes and user accounts, respectively. CyberRidge Ltd., the third startup that has raised funding, offers what it describes as a photonic layer transmission system. It’s designed to shield traffic in fiber-optic networks from eavesdropping attempts. 

Agentic email security 

Washington-based Sublime has closed a $150 million Series C round led by Georgian. The deal also drew contributions from Avenir, 01A, Index Ventures, IVP, Slow Ventures and Citigroup Inc.’s venture capital arm. The email security provider will use the funds to enhance its technology and grow its international presence.

Sublime’s platform uses artificial intelligence to protect employee inboxes from cyberattacks. It can spot malicious attachments, phishing messages and other threats. The company detects malicious activity by analyzing details such as the security of the infrastructure that was used to send a given email.

Earlier this year, Sublime expanded its platform with two new AI agents. The first, ASA, can analyze malicious emails reported by employees and generate a natural language summary of the threats they contain. Sublime’s other agent, which is known as ADE, generates malicious email filtering rules.

The company disclosed today that the two agents helped double its annual recurring revenue during the first half of the year. Sublime’s installed base includes Spotify AB, Snowflake Inc., Zscaler Inc. and other major tech firms.

Identity management automation

ConductorOne, which also counts Zscaler as a customer, provides an identity management platform with a set of AI automation features. Companies use it to regulate employee access to their applications. ConductorOne also lends itself to managing service accounts, which applications use to interact with one another.

The platform includes an AI assistant that can point out weak points in a company’s cybersecurity posture. It identifies employee accounts that should be deleted or assigned a fresh set of login credentials. According to ConductorOne, its platform also automates the task of reviewing application access requests. A built-in AI tool promises to reduce the amount of time that administrators must spend on the task by 95%.

ConductorOne has raised $79 million in Series B funding from a consortium led by Greycroft. The venture capital firm was joined by the CrowdStrike Falcon Fund, Accel, Felicis Ventures and others. ConductorOne will use the capital to hire more employees and build new features.

Optical security 

CyberRidge launched today with $26 million in funding from Awz, Arkin Capital, Redseed VC, Elron Ventures and the European Union’s Horizon-EIC program. The Tel Aviv-based startup has developed a system for securing data traffic in fiber-optic links such as subsea internet cables. It claims the technology can not only block today’s eavesdropping tactics, but also mitigate the future cybersecurity risks posed by quantum computers.

The light beams that zip across a subsea internet cable have different wavelengths. CyberRidge’s system spreads data across a large number of wavelengths and then encrypts it. According to the company, the traffic can only be read with a decryption key that is refreshed multiple times per second and “must be present at the exact moment the light signal arrives.”

CyberRidge says multiple organizations are currently piloting early-stage deployments of its system. 

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