Erik Nierenberg, Former Litmus CEO, Joins Invictus Growth Partners as a Partner to Accelerate Portfolio Value Creation

In addition, four seasoned B2B executives have joined the Invictus Guild as Operating Advisors: Stacey Epstein, Barry Zwarenstein, Nate Peace, and Gordon Mackintosh

SAN MATEO, Calif., Dec. 9, 2025 /PRNewswire/ -- Invictus Growth Partners ("Invictus"), a leading middle-market growth equity firm with more than $1 billion in assets under management, today announced that Erik Nierenberg has joined the firm as a Partner. Nierenberg will partner with current and future portfolio companies to accelerate growth and drive long-term value creation. Invictus also welcomed four senior executives to the Invictus Guild, its network of operating advisors, further expanding the firm's value-creation capabilities across the portfolio.

2025 has been a transformative year for Invictus. The firm more than doubled AUM with new oversubscribed funds totaling $574 million dedicated exclusively to enterprise cloud software, cybersecurity, and financial technology companies seeking both capital and operating resources to scale.

"The pace of innovation in cloud software and applied AI continues to accelerate, creating massive opportunities for companies that can scale into market leaders," said Erik Nierenberg. "I have worked with the Invictus team for years as part of the Invictus Guild and as a Board Director. Invictus combines deep operating and investing expertise with a unique data-science platform to help companies capture those opportunities. I'm excited to join the Invictus team and partner with companies to drive scale and growth."

Nierenberg brings more than two decades of B2B software leadership across sales, marketing, product, strategy, operations, business development, and M&A. Most recently, he served as CEO of Litmus, where he led the company for eight years during which the company achieved significant scale by profitably growing direct sales at a 55% CAGR and growing EBITDA profitability at a 63% CAGR. Litmus evolved from a single-product, single-channel business into a multi-product enterprise platform trusted by leading global brands. Under his leadership, Litmus was successfully acquired by Validity in April, 2025.

"Erik is a world-class operator who has already driven transformational impact for our portfolio as part of the Invictus Guild," said John DeLoche, Co-Founder and Managing Partner. "We're thrilled to welcome him as a Partner to extend that value creation more broadly across the firm."

Earlier in his career, Nierenberg held strategy, product, and go-to-market roles at Salesforce.com during its hyper-growth years. He also served as SVP and GM at Lynda.com (acquired by LinkedIn), was a consultant at Bain & Company, worked as an early-stage venture capitalist, and was part of the founding team at The Bridgespan Group. He has advised founders and CEOs at companies including 6sense, DataFox (acquired by Oracle), Udemy, Identified (acquired by Workday), and Bitly. At Invictus, he currently serves on the boards of Channelscaler and CYPHER Learning. Nierenberg holds a bachelor's degree with honors in Economics from Pomona College and an MBA from Stanford Graduate School of Business.

"Erik shares our values and our mission to Empower Excellence," added William Nettles, Co-Founder and Managing Partner. "His leadership has strengthened our value creation efforts, and we're excited to have him on the full-time team."

New Invictus Guild Operating Advisors

The Invictus Guild is a portfolio company success team of operating advisors that work closely with Invictus portfolio companies on value creation. Invictus also announced the addition of four new Invictus Guild operating advisors:

Stacey Epstein – Enterprise software veteran who helped build, scale, and exit iconic SaaS brands including SuccessFactors (from $10 million ARR to an IPO and subsequent acquisition by SAP for $3.4 billion), ServiceMax (less than $1M ARR to $1 billion acquisition by GE), Zinc (acquired), and Freshworks (IPO). She has served as CEO, CMO, Chief Customer Experience Officer, and Board Director.

Barry Zwarenstein – Seasoned finance leader who has guided technology companies through scaling, acquisitions, and IPOs, including Five9, Logitech, and Verifone. As longtime CFO of Five9, he helped grow the business from $60 million to over $1 billion in revenue; he brings strategic finance and capital-markets expertise to the Invictus portfolio.

Nate Peace – SaaS operator with deep expertise in customer success, operations, and post-sale growth. Currently SVP of Customer Success at LinkLive, he supports portfolio companies in retention, expansion, and operational excellence.

Gordon Mackintosh – Global go-to-market and channel leader who has built partner ecosystems at HPE, Juniper Networks, Cisco, and Extreme Networks. A CRN Channel Chief of the Year and Top 50 Most Influential Channel Chief, he helps accelerate revenue through world-class channel strategies.

Invictus Growth Partners is a middle-market growth equity firm with over $1 billion in assets under management, investing in bootstrapped and capital-efficient cloud software, cybersecurity, and fintech companies. The firm is deploying more than $574 million from recently closed funds and provides portfolio companies exclusive access to DIANE, its AI-driven value-creation platform, which has delivered a significant increase in direct sales conversion and can provide access to thousands of warm customer introductions. Invictus makes majority investments with $30 million to $100+ million equity checks. Visit us at www.invictusgrowth.com.

Contact: [email protected] 

SOURCE Invictus Growth Partners