How much has Onyx raised?

Onyx raised a $113M Series B led by Bessemer Venture Partners in July 2026, 4 months after leaving stealth.

Sell That S*it! · Pipeline · Issue 03 · Onyx

Mark, here's your cover.

You're on cover 03 of Pipeline, Issue 03, my magazine for 12 marketers building pipeline before the Series C. The cover is yours to post. If you tag me, I'll reshare it.

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Mark Loewenstein, VP of Marketing at Onyx, on the cover of Pipeline, Issue 03

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The caption it copies

Short

This is my first magazine cover.

Nobody prints Pipeline, so @Alex Muresan made it anyway. Issue 03 puts 12 marketers building pipeline before the Series C on its covers. I'm on cover 03, for Onyx.

Thanks @Reach AI for sponsoring the issue.

With the stat

I made the cover of Pipeline.

Issue 03 is the Series B issue, with 12 marketing and growth leaders whose companies raised $1.38B between them. I'm on cover 03. It's about Onyx raising its Series B 4 months after leaving stealth.

Thanks to @Alex Muresan for making it and to @Reach AI for sponsoring it.

Change anything you like. It's your post. After you paste it, retype @Alex Muresan and @Reach AI and pick each one from the list LinkedIn shows, because pasted names don't turn into tags (annoying, I know).

By Alex Muresan · Published October 12th, 2026 · Updated October 26th, 2026

Who is Mark Loewenstein?

Mark Loewenstein is the VP of Marketing at Onyx Security. Onyx builds a control plane for AI agents: it lets enterprises see, govern and secure the agents and models running inside the company.

About Mark Loewenstein

He is listed as VP of Marketing on Onyx's own team page.

About Onyx

Onyx builds a control plane for AI agents: it lets enterprises see, govern and secure the agents and models running inside the company. It left stealth in March 2026 and raised a $113M Series B led by Bessemer Venture Partners in July 2026, with Cyberstarts, TCV, Conviction and FirstMark. The company says revenue grew 4x in the 4 months between the two.

Why Mark is on the cover

Most security companies spend years explaining a new category. Onyx went from stealth to a $113M Series B in 4 months, so Mark is building pipeline for a category the market decided it needed almost overnight.

Questions about Mark and Onyx

What does Mark Loewenstein do at Onyx?: Mark Loewenstein is the VP of Marketing at Onyx Security.
What does Onyx do?: Onyx builds a control plane for AI agents: it lets enterprises see, govern and secure the agents and models running inside the company.
How much has Onyx raised?: Onyx raised a $113M Series B led by Bessemer Venture Partners in July 2026, 4 months after leaving stealth.